British Prime Minister Tony Blair will head to the United States this week for a visit with President Bush, Fox News learned Monday.

Officials said the two will meet at Camp David on Thursday. Blair is to arrive on Wednesday.

As Bush confronts Russian President Vladimir Putin over charges that Russian companies are supplying Iraqis with equipment that is aiding the enemy, Blair has held steadfast as the United States' closest and staunchest ally in the war against Iraq, and earned recognition for the loyalty.

Asked how the president's relations with Blair and Prime Minister John Howard of Australia, another coalition member with military forces on the ground, White House Press Secretary Ari Fleischer said the relationship is "very strong."

"I think that these leaders and a number of other leaders share a point of view that military force became necessary because Saddam Hussein refused to disarm. And they all are watching the same events unfold," he said.

As Iraqi leader Saddam Hussein appeared on Iraqi television Monday encouraging Iraqis to fight, Blair said the videotaped address offers no convincing evidence of whether Hussein is dead, alive or wounded.

"I mean, the truthful position is that we cannot be sure. We cannot be sure whether these recordings are pre-recorded. Some of them appear to be dated, but I don't think there is an exact science in this," Blair said.

Blair added that despite the challenges, nothing will change the outcome of the war:

"That we will encounter more difficulties and anxious moments in the days ahead is certain. But, no less certain — indeed more so — is coalition victory," he said.

Despite the odds against him, Blair has overcome public opposition in his country toward war. British polls show that after a tough fight in Parliament over Iraq and a weekend that brought British casualties, support for war has leapt from 29 percent in mid-February to 38 percent a week ago to 54 percent now.

Fox News' Jim Angle contributed to this report.