WASHINGTON (AP) — President Barack Obama will send 1,200 National Guard troops to help secure the U.S.-Mexico border, an administration official and an Arizona congresswoman said Tuesday, pre-empting Republican plans to try to force votes on such a deployment.

Obama will also request $500 million for border protection and law enforcement activities, they said.

The National Guard troops will work on intelligence, surveillance and reconnaissance support, analysis and training, and support efforts blocking drug trafficking. The troops will temporarily supplement border patrol agents until Customs and Border Patrol can recruit and train additional officers and agents to serve on the border, the administration official said.

The official, speaking on condition of anonymity ahead of a public announcement, disclosed the plans shortly after Obama met at the Capitol with Republican senators who pressed him on immigration issues including the question of sending Guard troops to the border.

WATCH ‘DAILY RUNDOWN’ COVERAGE OF OBAMA’S TROOP DECISION:

Visit msnbc.com for breaking news, world news, and news about the economy

Arizona Republican Sens. John McCain and Jon Kyl have been urging such a move and Republicans planned to try to attach it as an amendment to a pending war spending bill.

In a speech Tuesday on the Senate floor, McCain said the situation on the border has “greatly deteriorated.” He called for 6,000 National Guard troops to be sent to the U.S.-Mexico border.

“I appreciate the additional 1,200 being sent … as well as an additional $500 million, but it’s simply not enough,” McCain said.

Rep. Gabrielle Giffords, an Arizona Democrat, said in a statement that the administration would announce the deployments later in the day Tuesday.

Homeland Security and Pentagon officials have been jousting over the possible National Guard deployment for the better part of a year. Pentagon officials worried about perceptions that the U.S. was militarizing the border and did not want Guard troops to perform law enforcement duties.

Members of the National Guard are civilians who train once a week and one month during the summer in units that can be mobilzed for military duty or emergency relief.

Copyright 2010 The Associated Press.