Updated

President Bush is entering one of the most difficult weeks of his presidency, leading the nation in mourning over the space shuttle while bracing Americans for war and defending a budget proposal that promises record deficits.

He spoke with the leaders of Pakistan, Spain and India on Sunday, juggling condolence calls with efforts to build support for military action against Iraq.

The president arranged to meet Monday with NASA chief Sean O'Keefe, before O'Keefe briefed lawmakers.

Bush and his wife, Laura, are to fly to Johnson Space Center on Tuesday for a NASA memorial service for the seven astronauts killed Saturday.

The president was releasing a spending plan Monday for the budget year beginning Oct. 1 that offers a string of deficits for five years, with cuts in some popular programs and growth in others.

A senior administration official speaking Sunday night on condition of anonymity said the new budget would propose increasing NASA's budget from $15 billion this year to nearly $15.5 billion next year. The official did not know what the change for the space shuttle program would be.

A poll taken Sunday suggests the American public continues to support the shuttle program, with 82 percent in a CNN-USA Today-Gallup poll saying the manned flights should continue. That's about the same percentage who said it should continue after the 1986 Challenger explosion killed seven astronauts. The new poll of 462 adults had an error margin of plus or minus 5 percentage points

Bush planned to emphasize in a Monday afternoon event his request for $6 billion over a decade to quickly make available vaccines and treatments against bioweapons such as anthrax and plague.

Administration and congressional sources said Bush's plan envisions record deficits of $307 billion this year and $304 billion in 2004. The $2.23 trillion budget proposal does not take into account the tens of billions of dollars it would cost to invade Iraq.

The situation in Iraq also takes center stage this week.

Bush was to meet Wednesday with the prime minister Poland, the same day Secretary of State Colin Powell goes before the U.N. Security Council to present purported evidence of prohibited Iraqi weapons programs.

A session scheduled for Tuesday with the king of Bahrain was postponed indefinitely by Bush's trip to Houston, giving Bush some breathing room to put off talk of war while the nation grieved.

But White House spokesman Ari Fleischer said Bush's determination to disarm or confront Iraq would not be derailed by the shuttle catastrophe.

"The president views this as a tragedy that has touched the lives of the American people, and as a reminder of the risks of space flight," Fleischer said Sunday. "The president does not see it as connected to other events around the world. ... There is no change to the president's responsibilities to keep the peace and protect the American people from dangers around the world."

Bush listened intently in church Sunday as a minister said he had heard others say the shuttle's breakup was "God's way of getting back at us" for Bush's Iraq policies.

"That's hokum. That's just garbage," said the Rev. Luis Leon, rector of St. John's Church across Lafayette Square from the White House.

"What happened yesterday I think is the price that we pay for exploration, it's the price that we pay for the freedom that God has granted all of us," Leon said.

Bush bowed his head as a congregation member, Doug Volgenau, read aloud the names of the seven lost astronauts.

Volgenau prayed that "they may have a place in Your eternal kingdom."

"God's heart is more heartbroken than our own, and I believe they're already resting," Leon said.

After delivering an emotional televised statement Saturday on the Columbia, Bush kept a public silence Sunday.

Officials gathered Sunday in the White House Situation Room to monitor the investigations. Bush was being briefed throughout the day by chief of staff Andrew Card.

"People are busy keeping track of things, meeting, discussing, doing what they need to do to keep on top of that," John Marburger, head of the White House Office of Science and Technology Policy, said in a telephone interview.

Marburger would not say whether a separate White House investigation was under consideration. A White House "coordinated group" was ensuring that all information gleaned by various federal agencies was "coming through a funnel," Fleischer said. It will not generate its own conclusions about the disaster.

"We're going to have to get the forensic evidence, the debris and get the experts working on it, and begin to form these theories," Marburger said. "It's too easy to have theories based on this limited information. ... This is a problem with a lot of variables."