President Bush has continued his push for changes in U.S. immigration law during a visit to America's southern border.  Lawmakers are debating two competing bills.

President Bush told border patrol trainees in the southwest state of New Mexico that illegal immigration is a serious problem that undermines the rule of law and can threaten national security.

"Illegal immigration makes it tough on local communities," said Mr. Bush. "It puts a strain on public schools and strains state and local budgets. It brings crime to some of our communities. And we need to do something about it."

While illegal immigration is a major problem, President Bush says the debate over reforming that system must be conducted with dignity as America itself is a nation of immigrants.

"For generations, immigrants to this country have risked everything because of the dream of freedom," he reminded. "And they have assimilated into our society. And they have contributed to our economy. And they have contributed to the greatness of America."

President Bush wants Congress to spend more money for new fences and high-tech surveillance equipment as well as 6,000 more border patrol agents.

Because training those new agents will take time, the president is sending National Guard troops to help border patrol agents. Those troops will not be involved in direct law enforcement activities but will instead build roads and other infrastructure to free-up agents to better patrol the border.

National Guard officials say 800 troops are expected to be in place along the border by the middle of this month and the balance of the 6,000 troops should be there by August 1.

Forty percent of that force will be stationed in Arizona with the rest divided equally between California, New Mexico, and Texas.

A long-term solution to America's illegal immigration problem remains with U.S. lawmakers pushing competing bills in the Senate and House of Representatives.

The Senate bill focuses more on a guest worker program and how illegal immigrants who have been in America since January 2004 might become eligible for citizenship.

A bill passed by the House of Representatives deals only with border security and would make illegal immigration a felony.

Lawmakers expect to hammer out those differences in a conference committee, and President Bush is trying to lay the groundwork for that compromise.

Some of the opposition he is facing on this issue comes from members of his own Republican Party who are running for re-election from border districts and believe any accommodation for illegal immigrants amounts to amnesty.