Grand Rapids, Mich. ? As President Bush endorsed intelligence reforms Monday, Democratic challenger John Kerry mounted one of his most aggressive assaults on the White House record on terrorism, saying Bush had acted too slowly to deter attacks.

Campaigning in Michigan and Wisconsin a day after the administration raised the alert level for financial institutions in New York and Washington, D.C., Kerry also accused Bush of pursuing policies that encourage recruitment of new terrorists. And the Massachusetts senator urged Bush to call Congress into special session to take immediate steps against terrorism that Kerry said were long overdue.

“Sept. 11 was 2001,” Kerry shouted to more than 10,000 lunch-hour spectators who filled a downtown office plaza in Grand Rapids. “Sept. 11, 2002, came and went! Sept. 11, 2003, came and went! Sept. 11, 2004, is almost here.”

Only now is Bush “doing some of the things that some of us have been calling for all that period of time,” he told the sea of people surrounding a giant orange steel Alexander Calder sculpture. “We need leadership!”

After roars of applause, he continued: “If we’re at war, and it’s so urgent, we shouldn’t be waiting. We ought to get Congress back, and get the job done right now and make America safer.”

Kerry’s remarks came on the fourth day of his two-week “Believe in America” journey across the nation by bus, boat, train and plane.

On a weekend bus trip across the Rust Belt, he stressed plans to ease hardships of those hurt by job losses and rising living costs during Bush’s presidency. But on Monday, with the heightened terrorist warning dominating the news, Kerry went on the offensive against Bush’s national security record.

In a morning interview, he told CNN he would “fight a more effective war on terror” than the president.

“I believe this administration, in its policies, is actually encouraging the recruitment of terrorists,” Kerry said. “We haven’t done the work necessary to reach out to other countries. We haven’t done the work necessary with the Muslim world. We haven’t done the work necessary to protect our own ports, our chemical facilities, our nuclear facilities.”

At the White House, Bush responded to Kerry’s charges. In remarks to reporters gathered in the Rose Garden for his announcement that he would back proposals to create a job of national intelligence director and set up a new counterterrorism center, the president said his rival’s comments reflected a “misunderstanding of the war on terror.”

“It is a ridiculous notion to assert that, because the United States is on the offense, more people want to hurt us,” he said.

Bush took credit for “significant reforms” of counterterrorism since the 9-11 attacks. He cited creation of the Homeland Security Department and new protections for airports, harbors and borders. He also shunned the invitation to call Congress back from its August recess to weigh proposals on fighting terrorism.

“They can think about them over August, and come back and act on them in September,” Bush said.

Ed Gillespie, chairman of the Republican National Committee, said Kerry would not provide “strong, consistent leadership to a nation at war against global terror.” He faulted Kerry for accusations Sunday by a key supporter, former presidential aspirant Howard Dean, that politics drove the Bush administration’s terror alerts.

Kerry, who got a classified briefing on the latest alert by phone Sunday at a Michigan baseball field, told CNN he disagreed with Dean.