In his remarks, Trump said that “there’s not much difference” between a firearm and getting hit in the face with a rock.

“They want to throw rocks at our military, our military fights back,” the president said. “We’ll consider — and I told them — consider it a rifle. When they throw rocks like they did at the Mexico military and police, I say consider it a rifle.”

The Trump administration is weighing a series of policy options to limit asylum seekers’ ability to enter the United States.

White House officials had initially been planning a high-profile immigration-focused speech this week, but the mass shooting in Pittsburgh upended those plans. Still, Trump has pounced on a caravan of Central American migrants that is slowly making its way to the U.S.-Mexico border in an effort to rally his base ahead of Tuesday’s midterm elections. In recent days, he has floated the idea of issuing an executive order to end birthright citizenship, a proposal that experts say wouldn’t survive legal challenges.

Trump’s comments that troops at the border would treat rock-throwing the same way as a firearm raises questions about the possibility for violent confrontation between migrants and troops or Border Patrol agents.

The president this week ordered 5,200 troops to the border, and told reporters Wednesday that he might increase that number to 15,000. The troops will not conduct law enforcement operations, but some of them will be armed for self-defense, administration officials said Monday.

Under existing rules of engagement, deployed troops should use deadly force only “when there is a reasonable belief” the subject “poses an imminent threat of death or serious bodily harm.”

U.S. Customs and Border Protection’s use-of-force handbook offers similar guidance. The handbook says agents should not discharge firearms in response to thrown or launched projectiles unless the agent has reason to believe the subject “poses an imminent danger of serious physical injury or death” to the agent or another person.

The handbook suggests agents seek cover or distance themselves from the threat in such a situation.

Trump also said Thursday that the administration would seek to detain all migrants arrested at the border, including families and asylum seekers. To accomplish that, he said, the troops would build tent cities on the border.

“We’re putting up massive cities of tents,” he said. “The military is helping us incredibly well. … We have thousands of tents, we have a lot of tents, we have a lot of everything. We’re going to hold them right there, we’re not letting them into our country.”

The 1997 Flores settlement agreement limits to 20 days the time a child can be kept in detention with a parent. A ruling earlier this year suggested parents may waive that right, but the Homeland Security Department is already at capacity with family detention space. Under the agreement, family detention centers must also be nonsecure, state-licensed facilities.

“We’re working on a system where they stay together,” Trump said of migrant families, without offering more details.

The president did not explain how the migrant tent cities would be funded, but resources for detention facilities have been an impediment to mass detentions during the course of his administration.

In a January 2017 executive order issued just days after taking office, Trump called for migrants caught at the border to be detained pending the outcome of removal proceedings. But budget limitations and legal restrictions have kept that from becoming a reality.

Rep. Bennie Thompson (D-Miss.), the top Democrat on the House Homeland Security Committee, called Trump’s speech “a political stunt aimed at whipping up fear and xenophobia just days before the election.”

Thompson said in a written statement that Trump and Republicans “have sunk to new lows with hateful rhetoric and racist campaign ads.” Trump on Wednesday tweeted an inflammatory video that featured an undocumented immigrant convicted of killing two law enforcement officers.

The White House and the Department of Homeland Security have been weighing an executive action and a regulatory change that would restrict certain migrants’ ability to seek asylum.

People familiar with the White House maneuvers told POLITICO last week that the administration could seek to bar certain asylum seekers under a federal statute that authorizes the president to suspend entry of foreigners deemed “detrimental to the interests of the United States.”

The statute, 212(f) of the Immigration and Nationality Act, served as part of the legal basis for Trump’s travel ban executive orders. The Supreme Court in June upheld the third version of the policy, which critics labeled a “Muslim ban.”

A person familiar with the planning said the fast-track regulation wasn’t ready in time for Thursday’s speech but remained under consideration.

The White House has also weighed a reprise of its family separation policy, which sparked widespread opposition earlier this year. Under the plan, migrant parents would be offered the “binary choice” to remain in detention with a child or have the child sent to a shelter where they could be released to a sponsor, POLITICO reported in October.

Health and Human Services Department officials worried Thursday that Trump could embrace the controversial policy in his speech, according to a source briefed on the deliberations. DHS Secretary Kirstjen Nielsen called HHS Secretary Alex Azar early in the day, which put officials on high alert, the person said.

The Trump administration previewed a wide range of asylum actions in its fall regulatory agenda and could potentially fast-track one or more of those measures, according to Jessica Vaughan, a policy director with the Center for Immigration Studies, which advocates lower levels of immigration.

One option could be a regulation to toughen the standard for a migrant to claim “credible fear” of persecution, the first step in an asylum claim. The administration said in its fall regulatory agenda that it intended to issue a proposed rule on the issue in September 2019.

Another planned regulation would narrow asylum standards to align with new immigration court precedent. Attorney General Jeff Sessions in June moved to block most migrants from obtaining asylum based on gang victimization or domestic violence. The administration slated a related proposed rule for December.

While the measures are under consideration as part of broad efforts to reduce migrant flows at the border, it remains unclear whether they could be part of the executive action Trump plans to announce next week.

Trump has come under criticism from Democrats and Republicans alike for his unsubstantiated claims about the migrant caravan, casting the group of people as an “invasion” and warning without evidence that the group contains gang members and “unknown Middle Easterners.”

In his speech Thursday, Trump said migrants arriving at the border had engaged in a “rampant abuse” of the asylum system and displaced legitimate asylum seekers. He said migrants parrot certain phrases to clear the baseline to begin seeking asylum.

“They understand the law better than the lawyers understand the law,” he said.

The president hammered Democrats as the party of “open borders” and said they favored granting a broad range of public benefits to undocumented immigrants.

“Once [migrants] arrive, the Democrat Party’s vision is to offer them free health care, free welfare, free education and even the right to vote,” Trump said. “You and the hardworking taxpayers of our country will be asked to pick up the entire tab. That’s what’s happened. … In many cases, they’ve got some big medical problems before they get here.”

Undocumented immigrants have access to few federal benefits, but can obtain emergency medical care, public education for children, and services through a health and nutrition program for pregnant women and young children.

The pro-migrant Physicians for Human Rights said Thursday that Trump’s attempt to deter asylum seekers violated international refugee agreements.

“Most of these migrants are coming from countries where they face widespread violence and intimidation, and many have no choice but to flee,” said Kathryn Hampton, an asylum program officer with the group. “They have a legal right to seek asylum and to have their cases heard once they have arrived on U.S. soil.”

Overall, migrant arrests at the border in fiscal year 2018 remained below the average level under President Barack Obama and far below the high levels of the 1990s and early 2000s.

Gabby Orr, Dan Diamond, Rebecca Morin and Wesley Morgan contributed to this report.