SCOTTSDALE, Ariz. (AP) — President Bush on Wednesday signed a homeland security bill that includes an overhaul of the Federal Emergency Management Agency and $1.2 billion for fencing along the American-Mexico border to stem illegal immigration.

Standing before a mountainous backdrop in Arizona, a state that has been the center of much debate over secure borders, Mr. Bush signed into law a $35 billion homeland security spending bill that could bring hundreds of miles of fencing to the busiest illegal entry point on the American-Mexican border.

Mr. Bush said enforcement alone will not stop illegal immigration, and urged Congress to pass his guest worker program to legally bring in new foreign workers and give some of the country’s estimated 11 million illegal immigrants a shot at American citizenship.

“The funds that Congress has appropriated are critical for our efforts to secure this border and enforce our laws, yet we must also recognize that enforcement alone is not going to work,” Mr. Bush said at the bill-signing ceremony tucked into his three-day campaign fundraising trip to the West. “We need comprehensive reform that provides a legal way for people to work here on a temporary basis.”

Among other things, Mr. Bush said the homeland security funding bill deploys nuclear detection equipment to points of entry, raises safety security standards at chemical plants, provides better tools to enforce immigration laws and provides vehicle barriers, lighting and infrared cameras to help catch illegals trying to cross the border.

“It’s what the people in this country want,” Mr. Bush said. “They want to know that we are modernizing the border so we can better secure the border.”

President Fox, who has spent his six-year term lobbying for a new guest worker program and an amnesty for the millions of Mexicans working illegally in America, has called the barrier “shameful.” He compares it to the Berlin Wall.

Some Democrats criticized the homeland security spending bill as too meager.

Rep. Ed Markey, D-Mass., a senior member of the House Homeland Security Committee, said the homeland security spending bill does not improve screening of cargo carried on passenger planes, does not provide money to buy and install advanced explosive-detection equipment and does not include strong enough security requirements to protect against a terrorist attack on chemical plants.

“There are nightclubs in New York City that are harder to get into than some of our chemical plants,” Mr. Markey said.