Thousands protest against the Iraq war in San Francisco, California, March 18, 2007. [Reuters]

WASHINGTON - As the fourth anniversary of the war approached with another violent day in Iraq, US Defense Secretary Robert Gates said on Sunday it was too early to evaluate whether the latest U.S. strategy was working but "so far, so good."

American generals say it will probably be summer before the impact of additional U.S. troops sent to Iraq can be fully assessed, and have warned that the troop surge could have a "squirting effect" where al Qaeda and insurgents would operate from elsewhere, Gates said.

American public opinion has turned increasingly against the Iraq war and anti-war sentiment propelled Democrats into the majority in Congress. The fourth anniversary of the Iraq war this week was marked by anti-war protests during the weekend.

Iraqi police on Sunday found the decapitated and bound bodies of nine policemen in Anbar province, where hundreds were earlier poisoned by chlorine gas bombs which U.S. commanders blamed on al Qaeda.

President George W. Bush in a new strategy this year ordered more U.S. troops to Iraq to focus on stabilizing Baghdad and restive Anbar province. Nearly 30,000 additional combat and support troops are being sent in an effort to curb sectarian and insurgent violence.

"I think that the way I would characterize it is so far, so good. It's very early," Gates said in an interview on CBS' "Face the Nation" program.

"I would say that the Iraqis are meeting the commitments that they have made to us," he said, pointing out that Iraqis have sent troops, allowed security operations in all neighborhoods and shown little political interference with military operations.

Bush has repeatedly opposed setting timelines for withdrawing U.S. troops from Iraq. But the House of Representatives, now led by Democrats, is preparing to debate a proposal that would tie approval of emergency war funds to a troop pullout by September 2008.

NO CHARADE

"The president has said he will veto it if it passes. That is clear to the Democrats in the Congress," Stephen Hadley, White House national security adviser, said on ABC's "This Week" program. "Our plea is, let's not go through this charade."

He reiterated the Bush administration's stance that premature troop withdrawal from Iraq would leave security to Iraqi forces that cannot yet cope with it on their own and allow groups like al Qaeda to establish a base from which to attack the United States.

But Hadley on CNN's "Late Edition" said he agreed with assessments reported by The Washington Post that al Qaeda's "hands are full in Iraq," but that the group has the intention to attack the United States.

Al Qaeda in Iraq, which is currently led by an Egyptian, has "made no bones" that once it establishes a firm base in Iraq, that it intends to try to destabilize neighbors and eventually attack the United States, said Gates, who is a former CIA director. "They've not made any secret of that."

Zbigniew Brzezinski, former national security adviser to President Jimmy Carter, said the Bush administration's logic was flawed that fighting al Qaeda in Iraq would prevent it from attacking the United States.

"What the administration fails to understand, and it's a fundamental historic error, is that we cannot be acting like an imperial power in the post-imperial age, like a colonial power in a post-colonial age," he said on CNN.

"The only way to eradicate terrorism is to have the support and consensus of all the moderates in the countries that potentially breed terrorists. And not trying to do it by ourselves with means which increasingly alienate people," he said.