For years, the debate raged within the CIA: Should the United States hunt down and kill its terrorist foes, or would Israeli-style "targeted killings'' only invite retribution and feed an endless cycle of violence?

The debate ended Sunday, current and former intelligence officials said, when the CIA incinerated a carfull of Al Qaida operatives in northern Yemen with a laser-guided Hellfire missile.

"There was discussion about this for years in the CIA,'' said one former agency official with extensive experience in the Middle East.

"The discussion is now over and the operations have begun.''

The risks remain. Even those who applauded Sunday's strike said in interviews Tuesday that it is sure to inflame militants, including those belonging to the Al Qaida network, and expose U.S. diplomats and other overseas officials to possible retaliation.

The attack triggered outrage in some quarters of the Arab world and forced U.S. officials into the difficult position of defending a tactic it has criticised Israel for using.

But Bush administration officials made it clear that they see those risks and diplomatic discomforts as worth enduring when confronted with an opportunity to kill a high-ranking Al Qaida figure linked to previous attacks and considered likely to be planning more.

In fact, U.S. officials and top Pentagon advisers said Tuesday that Al Qaida should expect more of the same.

"We've got new authorities, new tools and a new willingness to do it wherever it has to be done,'' one administration official said. Neither the CIA nor the White House would publicly confirm the U.S. role in the strike, which is believed to have killed Qaed Senyan Al Harthi, who is suspected of being involved in the 2000 bombing of the Cole destroyer, an attack in which 17 U.S. sailors died. But administration officials openly relished what was widely viewed as a significant and symbolic U.S. victory.

Deputy Defence Secretary Paul Wolfowitz called the strike a very successful tactical operation.''

"We've got to keep the pressure on everywhere we're able to,'' he said on CNN.

"We've got to deny the sanctuaries everywhere we're able to, and we've got to put pressure on every government that is giving these people support to get out of that business.''

White House spokesman Ari Fleischer declined to discuss the attack specifically but said: "The president has talked about a shadowy war where terrorists are going to try to hide. ... We're going to be on the lookout for them when they emerge.''

Sunday's mission was in keeping with the so-called Bush doctrine that, among other things, commits the nation to pre-emptive military strikes in the U.S.-declared war on terrorism. It was carried out by an unmanned CIA surveillance plane armed with laser-guided missiles. The Predator drones had been patrolling Yemen in recent months, tracking the movements of dozens of Al Qaida figures who have been operating in the country's barren northern territory.

Until Sunday, U.S. strikes on suspected Al Qaida members had been confined to the war theatre in Afghanistan.

Elsewhere, the CIA's activities had appeared to consist mainly of assisting in raids and other operations conducted jointly with foreign intelligence services.

At the State Department, spokesman Richard Boucher refused to discuss the attack in Yemen and trod carefully around questions on whether U.S. involvement in the strike contradicts long-standing U.S. disapproval of so-called targeted killings.

The State Department has repeatedly criticised Israel for using such tactics against Palestinians.

Asked whether the United States has altered its opinion, Boucher replied, "Our policy on targeted killings in the Israeli-Palestinian context has not changed.''

He went on to say that the U.S. position reflects concern that such killings harm prospects for peace negotiations.

Those reasons, he said, "do not necessarily apply in other circumstances.''

Israeli scholars rejected such distinctions and said the attack in Yemen is tantamount to a U.S. endorsement of the Israeli policy of pre-emptive attacks on militant foes.

The U.S. shift, the scholars said, shows that the Bush administration has rejected the long-held American view that refraining from violence offers at least some protection from retaliation.

"Israel knows that it's going to be attacked no matter what it does,'' said Barry Rubin, head of the Global Research and International Affairs Centre.

"The U.S. situation has become more like the Israeli situation. It is the impact of September 11.''

Current and former intelligence officials said reprisals are possible, if not inevitable.

"Not everybody has been gung-ho about going out and doing this,'' said a former CIA official previously involved in high-level counter-terrorism missions.

"It may be the right policy, but it's not going to be without consequences."

Others, however, said September 11 showed that U.S. restraint earned it no protection from Al Qaida and that the show of force in Yemen was long overdue.

"Maybe they'll try to do something else to us,'' another former senior CIA official said.

"The fact is, we've been getting shot at for the last 30 to 40 years. The weaker they think you are, the more they'll go after us.''

Boucher, the State Department spokesman, said he was not aware of whether U.S. embassies are taking extra precautions in the wake of the missile strike but noted that they are "already at a very high state of security.''

The attack in Yemen prompted criticism from some in the Arab world. The London-based Arab newspaper Al Quds Al Arabi carried an editorial Tuesday condemning the attack.

"We believe the Americans are adopting the Israeli style of bombing - it is appaling,'' editor Adelbari Atwan wrote.

"This is not the work of a civilised democratic power but in the style of Osama bin Laden.''
Atwan predicted that the attack will antagonise Arabs and "will encourage membership (in) Al Qaida .''

The Yemeni government, which is cooperating with the United States in the war on terrorism and is said to have permitted the attack, offered no immediate comment on the incident. Many experts said it is likely to inflame anti-American sentiment already widespread in the country.

But Yemen's president, Ali Abdullah Saleh, issued a statement Tuesday timed for the start of Ramadan urging Al Qaida members to "repent'' and "renounce all means of violence.''

The official Yemeni news agency cited reports from local tribesman near the scene of the attack, about 150km east of Sanaa, confirming that Al Harthi was among those killed. Al Harthi had been under U.S. surveillance for months.

A onetime bodyguard to Bin Laden, he was believed to be Al Qaida's operational leader in Yemen, where many Al Qaida members have fled from war-torn Afghanistan.

Some former intelligence officials said the strike is certain to deliver a psychological blow to Al Qaida, perhaps explaining why word of U.S. involvement in the attack leaked so quickly from the Bush White House