Washington ? On the bloodiest day for the U.S. military in more than seven months, Defense Secretary Donald Rumsfeld insisted Sunday the Bush administration’s plan to improve security in Iraq was on track, with no need for additional U.S. troops as Iraqis are quickly trained to fill any manpower gaps.

“In a long, hard war, we’re going to have tragic days, as this is,” Rumsfeld said on ABC’s “This Week.” “But they are necessary. They are part of a war that’s difficult and complicated.”

President Bush, visiting his ranch in Crawford, Texas, made no public appearances Sunday and offered no comment on the day’s events: the downing of an Army helicopter that left at least 16 dead, the killing of a U.S. soldier in a bomb attack in Baghdad and the deaths of two American civilian contractors in roadside mine blast. As a new Washington Post-ABC News poll showed 51 percent of Americans disapprove of the president’s handling of Iraq, his Democratic rivals pressed their case that the administration has bungled postwar operations and has no strategy for ending U.S. involvement.

With Sunday’s deaths, the total number of U.S. troops who have died in Iraq has increased to 379 — almost two-thirds of them since Bush, standing in front of banner declaring “mission accomplished,” announced an end to major combat operations on May 1.

Rapid ‘Iraqification’

Blunting new calls from Capitol Hill to dispatch more U.S. troops, Rumsfeld said “over 100,000” Iraqi forces already had been trained to provide security, and that number would double by next September. Rumsfeld’s number of Iraqi forces is 15,000 higher than what the U.S. occupation authority and national security adviser Condoleezza Rice have said in the past week and represents a 40 percent increase from administration estimates a month ago.

The administration has stressed a rapid “Iraqification” of the security situation as attacks against U.S. targets have dramatically increased in recent weeks. But, paradoxically, the attacks appear to be increasing in sophistication and accuracy as the administration asserts that more of the security is being turned over to Iraqis.

The U.S. military has lost CH-47 Chinook transport helicopters before, including one shot down by heavy machine gun fire in Afghanistan. But this might be the first time a Chinook — or any other U.S. military aircraft — has been lost to a handheld surface-to-air missile.

Two influential senators said Sunday the answer might be an increase in U.S. forces. Sen. Joseph Biden, D-Del., the ranking minority member of the Senate Foreign Relations Committee, said on CBS’s “Face the Nation” that “in the short-term, we may need more American forces in there while we’re training these people up.” He said the administration also needed to enlist European allies by giving them a greater say in the postwar enterprise. Sen. Richard Lugar, R-Ind., the committee chairman, echoed Biden’s comments on the same program.

But Rumsfeld said that although the number of U.S. troops in Iraq had declined from 150,000 to 130,000, “the total number of the security forces in the country has been going up steadily” because forces contributing from other countries has remained steady at 30,000 and the number of Iraqi forces “have gone from zero on May 1st up to over 100,000 today.”

U.S. soldiers search rubble after a U.S. Chinook helicopter carrying dozens of soldiers to leaves abroad was struck by a missile and crashed west of Baghdad. Sunday's crash killed at least 16 soldiers and wounded more than 20 others, the U.S. command and witnesses reported.

Rumsfeld said “it’s the totality of those three that needs to go up and it is going up steadily. And there has not been a need for additional U.S. forces.”

Minimizing attention

Aides said Bush had no plans to appear in public before he leaves the ranch for seven hours Monday to travel to Birmingham, Ala., to raise money for his re-election campaign and speak about the economy. The White House issued a statement, in the name of a spokesman, invoking the attacks of Sept. 11, 2001, and pledging that the United States “will prevail in this critical front in the war on terror, because the stakes are too high to do anything less.” The statement did not mention the Chinook crash, but included a general statement of gratitude to “the brave men and women in the military and elsewhere” who make sacrifices to make the world safer.

Just three weeks ago, White House officials had mounted a public relations offensive in which Bush and his senior aides accused news organizations of underplaying progress in Iraq, with Bush denigrating “the filter” of national networks and newspapers. But nearly every day since then, some new attack in Iraq has made that strategy harder to pursue. During a Southern swing Saturday, Bush largely ignored the death toll in Iraq, referring specifically to Iraq only once in four speeches totaling 72 minutes.