WASHINGTON (AP) — The Latest on President Donald Trump and immigration (all times local):

4 p.m.

A powerful House chairman says he may want outgoing Homeland Security Secretary Kirstjen Nielsen to testify before his panel about President Donald Trump's shakeup of the agency.

Oversight Committee Chairman Elijah Cummings says he hasn't decided, but his panel is "going to take a look at it."

The Maryland Democrat adds, "I don't know why the president has done what he has done, and I certainly would be interested in talking to" officials at the agency.

Asked Tuesday if he will call Nielsen in to talk to the panel, he answered: "We may. But I haven't decided."

Nielsen resigned Sunday after a difficult tenure in which she clashed often with Trump, who wanted a harder-line immigration policy. More leaders are expected to leave the agency.

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3 p.m.

The U.S. Border Patrol says it has set a new monthly record for apprehensions of families at the southern border, driven primarily by a surge of parents and children leaving Central America.

The agency said Tuesday that it apprehended 92,607 people at the U.S.-Mexico border in March.

Just over 53,000 of the people apprehended were parents and children traveling together, which the Border Patrol refers to as "family units." That breaks a record set in February, when the agency apprehended 36,000 parents and children. Another 8,975 were children traveling alone.

The large numbers of families have forced many line agents into humanitarian roles and have strained detention facilities built when the Border Patrol primarily apprehended single adult men.

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1:45 p.m.

Top Republicans are expressing concern over vacancies at the Department of Homeland Security and cautioned President Donald Trump off more shake-ups after the resignation of Secretary Kirstjen Nielsen.

Sen. Susan Collins of Maine said Tuesday having participated in creating the department more than a decade ago she knows "these are vital positions."

Iowa Republican Sen. Chuck Grassley made both a public and private plea to the White House not to dismiss career homeland security officials. He said he spoke to Chief of Staff Mick Mulvaney but would only know if Trump heard the message "if they don't get fired."

As Trump considers replacements at DHS, Republican John Cornyn of Texas, said he hoped the administration would work in "collaboration, consultation" with the Senate before sending nominees for confirmation.

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12:41 p.m.

President Donald Trump says he's not looking to reinstate the much-criticized practice of separating migrant families at the border with Mexico. But he says many more migrants are streaming toward the U.S. through Mexico because the practice is no longer in place.

Says Trump: "I'm the one that stopped it." He claims his predecessor, President Barack Obama, is the one who separated children from their families.

Trump ended the practice under pressure last year after footage of scores of migrant children housed in fenced-off cages at border facilities was broadcast widely. Trump's allies are pressing for a harder line on immigration after he cleaned house at the Homeland Security Department.

Trump says "once you don't have it," meaning the family separation policy, "that's why you see many more people coming."