¡¡   WASHINGTON, May 13 (Xinhua) -- U.S. President George W. Bush isconsidering substantially increasing the presence of National Guard troops on the country's borders with Mexico, The Washington Post reported Saturday.

    Bush will push next week for a broad overhaul of the nation's immigration laws and plans to tighten security on the borders, and he is expected to use a prime-time television address Monday to outline his plans and then visit the U.S.-Mexico border on Thursday to highlight the problem of illegal immigration.

    National Guard troops are already deployed under state emergency declarations in New Mexico and Arizona, and administration officials are exploring ways to allow governors to deploy troops across state lines to help seal the porous borders with Mexico, the newspaper said.

    White House officials were intentionally vague on the National Guard deployment, instead emphasizing a plan to hire more contractors to fill administrative posts with the Border Patrol so more agents could be deployed to the frontiers. Pentagon officials emphasized that any military support would be limited.

    "Any additional (Defense Department) support for Customs and Border Protection (CBP) operations would be temporary in nature and allow CBP to recruit and train additional personnel," military spokeswoman Cynthia O. Smith was quoted as saying.

    The number of illegal immigrants in the United States is estimated at up to 12 million, and rallies in recent months have brought millions of them to the streets of Washington, Los Angeles,Dallas, Chicago and other cities.

    The House of Representatives passed a bill last December that would make illegal immigrants felons and build hundreds of miles of fence along the Mexican border without offering avenues to legality for undocumented workers.

    Senate leaders meanwhile have agreed to take up the issue of immigration again, more than a month after a bipartisan compromise measure collapsed, and are preparing for difficult negotiations with the House. The Senate bill would tighten border security, create a guest worker program and grant illegal immigrants a pathway to citizenship. Enditem