US: 'Everything on table' to block migrants at border

Nielsen's trip to the border came after the Pentagon approved a request for additional troops at the southern border, expected to total at least 800 and possibly more than 1,000. And the White House is looking at new border security measures, including one plan that would use the same mechanism as Trump's travel ban to block migrants from seeking asylum in the U.S, according to two people familiar with the discussion. They spoke on condition of anonymity to discuss the idea, which they stressed was still in the early planning stages and had yet to be decided.

"We are looking at every possible way within the legal construct that we have to make sure that those who don't have the legal right to come to this country do not come in," Nielsen said.

The president has stepped up his focus on immigration in the days leading up to the Nov. 6 elections that will determine which party controls Congress, focusing on a caravan of migrants heading north through Mexico that is about 1,000 miles away but dwindling in size.

"I called up the military," Trump said at a meeting of young black conservative leaders. "We're not letting them in, they ought to go back now because we're not."

Any attempt by Trump to curtail the rights of migrants to seek asylum is bound to draw legal challenge.

Andrea Guerrero, executive director of Alliance San Diego, said it would be "a very drastic action that would have disastrous practical implications for our asylum obligations, for our moral and legal obligations."

"We know that civil rights attorneys are preparing to litigate right now," she said. "They're preparing to litigate right away. I don't know if (Trump) cares if he wins the litigation. He wants to score political points ... it's all part of the same political ploy to stoke fear for political reasons and build more walls."

The federal government recently completed construction on a two-mile section of fencing that's 30-feet tall. Nielsen called it a significant accomplishment to keep immigrants out. The structure is separate from a concrete wall prototype that the government has built near San Diego as part of Trump's signature campaign promise during his 2016 White House campaign.

"Let me be clear: Walls work," Nielsen said.

New details also began to emerge Friday about the military deployment on the border.

A Defense Department official said the mission is authorized from Oct. 30 to Dec. 15 and will operate in border areas of California, Arizona and Texas. The official, who spoke on condition of anonymity to provide details that have not yet been publicly announced, said the troops will not be involved in detaining migrants.

In a brief written statement the Pentagon gave several examples of assistance they would provide. These include barricades and fencing; helicopters and airplanes to move Border Patrol personnel, and medical teams to triage and treat patients and prepare them for commercial transport. It also will provide personal protective gear and temporary housing for Border Patrol personnel.

Trump earlier this year ordered the deployment of National Guard members to the U.S.-Mexico border to respond to a spike in illegal border crossings. But those members remain under the control of the governors of the states where they're positioned, and their activities are limited to supportive roles, such as providing surveillance.

There already are about 2,000 National Guard troops on the border.

___

AP Writers Bob Burns and Colleen Long contributed to this report from Washington.