WASHINGTON - The House will consider new legislation to address the treatment of migrants at the southern border, Speaker Nancy Pelosi said Monday - less than two weeks after passage of a $4.6 billion emergency spending package left scores of Democrats angered about a lack of accountability for the Trump administration.

"Legislation is necessary," Pelosi, D-Calif., said in a letter to Democrats, pointing to House provisions that were left out of the Senate-negotiated spending bill that ultimately passed last month - including medical care standards for migrants in U.S. custody, a 90-day limit on children's stays in federal "influx shelters" and guaranteed access to border facilities without notice for members of Congress.

Those provisions, however, are unlikely to be taken up by the Republican-controlled Senate and stop short of the full 2020 border spending bill that some Democrats are hoping to pass this month. But the announcement underscores how Pelosi is under increasing pressure from liberals to take a stronger stance against President Trump on the border crisis after the emergency bill bitterly divided her caucus.

Pelosi's letter came after a Sunday announcement of the coming month's floor schedule from House Majority Leader Steny Hoyer, D-Md., which did not include any specific immigration legislation. Hoyer said the House would focus on bills authorizing Pentagon activities for the coming year, raising the minimum wage and reducing health-care costs.

"In addition, House Democrats will continue to monitor the humanitarian crisis created by President Trump at our Southern border, and we are prepared to take action," he said.

The legislation Pelosi is contemplating, however, may not be enough to placate many Democrats - including members of the Congressional Hispanic Caucus, whose chairman last week pushed for quick consideration of the 2020 Department of Homeland Security spending bill.

Rep. Joaquin Castro, D-Texas, said party leaders "need to leverage our power in the House of Representatives" by moving forward with next year's spending to avoid another situation where the House is forced to accept a Senate-negotiated product ahead of a do-or-die deadline.

House Democratic aides said last week, however, that there were no further plans to move forward with 2020 spending bills this month.

The discord among House Democrats came as top administration officials stepped up its efforts to highlight the significant challenges at the border, where migrants from Central America have been apprehended at levels not seen for at least a dozen years.

Vice President Mike Pence announced Monday that he and his wife, Karen, would travel to McAllen, Texas, with both Democrats and Republicans on the Senate Judiciary Committee on Friday. "The Senate passed bipartisan humanitarian relief - but much more must be done to SECURE our border & end this crisis!" Pence said on Twitter.

The actual list of attendees has not been finalized, according to congressional aides, but the committee's chairman, Sen. Lindsey Graham, R-S.C., told members of his committee that he planned to go to McAllen for a border visit and that all were welcome, according to a Senate official with knowledge of the discussions.

It's unclear who among Democrats will attend with Pence. Sen. Richard Durbin, D-Ill., who is deeply influential in the Senate Democratic Caucus on immigration issues, is checking if he can rearrange his weekend schedule to accommodate the visit, according to a spokeswoman. Sen. Patrick Leahy, D-Vt., who helped negotiate the border spending package that Pence touted in his Monday tweet, recently visited the border, as have his staffers on the Senate Appropriations Committee, a spokesman said.

While in Texas, Pence and the senators will tour the so-called "Ursula" facility run by Customs and Border Protection - the largest processing center for migrants located on Ursula Avenue in McAllen, according to a tentative itinerary of Pence's visit obtained by The Washington Post. The center became a central processing facility in 2014 amid the increased numbers of unaccompanied migrant children arriving at the southern border, and Pence and the senators will view the efforts on the part of federal officials to offer care for migrants, as well as how families are processed.

The McAllen visit also includes a boat tour of the Rio Grande for Pence and the senators to observe the "operational and border environment," a briefing with officials from CBP and Immigration and Customs Enforcement, and a tour of the Anzalduas International Bridge, a major port of entry in the border town where the officials will be able to see the "influx of migrants waiting in line as well as (CBP officials) managing the daily traffic and commerce," according to the itinerary.

In her letter, Pelosi also said the House would vote soon on a measure holding Attorney General William Barr and Commerce Secretary Wilbur Ross in contempt of Congress over their refusal to cooperate with an Oversight and Reform Committee investigation into the Trump administration's attempts to add a citizenship question to the 2020 Census.

"It is essential to who we are as a nation and how we meet the needs of the American people," Pelosi said of the census. "In both the case of the Census and the abhorrent conditions for children and families at the border, we must hold the Trump administration and the GOP accountable."

As a postscript, Pelosi also noted that she has, by bipartisan request, invited members of the U.S. women's national soccer team to the Capitol to celebrate their World Cup victory. The team's visit to the White House remains in question following sharp criticism of Trump from star forward Megan Rapinoe and other players.

This article was written by Mike DeBonis and Seung Min Kim, reporters for The Washington Post.