Asked whether he would express regret for Friday's attack, spokesman Scott McClellan declined to confirm that the United States had carried it out but said Washington would continue to target the terrorist network.
"I don't ever get into discussing any specific operational activities, or even alleged operational activities," he told reporters amid anger in Pakistan over the strike.
"Pakistan is a valued ally in the war on terrorism. We work closely with Pakistan and others to go after al-Qaeda and bring their leaders to justice, and we will continue to do so," said Mr McClellan.
"The president made it very clear that we are going to continue to pursue al-Qaeda leaders and bring them to justice. There are a number that have been brought to justice, and we will continue to do so," he said.
"Al-Qaeda continues to seek to do harm to the American people. There are leaders that we continue to pursue, and we will bring them to justice. The American people expect us to do so, and that's what this president is committed to doing," he said.
Prodded on whether it might be beneficial for the Bush administration to express regret if US airstrike accidentally hit civilians, McClellan replied: "I think you've heard our comments about matters of that nature in the past. If I have anything additional to add, I will."
Pakistan Prime Minister Shaukat Aziz said that Islamabad cannot accept actions like an air strike on a village that killed 18 people, adding that he will bring it up when he visits Washington this week.
Officials in the tribal zone where the missile landed said separately that the strike was aimed at foreign militants invited to a dinner and that up to five of them were killed, the first such confirmation by Pakistan.
The air raid on Friday in Damadola a village in the Bajur tribal agency, targeted al-Qaeda's deputy leader, US intelligence sources have said, although Washington has not confirmed it launched the attack.
Pakistan lodged an official protest with the US embassy on
Saturday and thousands of people chanting "Down with America" took to the streets in angry protests in major cities the following day.