Treasury Secretary John Snow has postponed a planned weeklong trip to Africa in order to deal with various congressional issues, ranging from the ports security uproar to the urgent need to raise the government's debt ceiling, a Treasury official said Monday.

Tony Fratto, Snow's chief spokesman, said Snow had decided that a variety of issues pending before Congress this week made it necessary for him to delay a trip he had scheduled to meet with finance officials in Tanzania and South Africa. Fratto said the trip would be rescheduled but that a new date had not been selected.

Fratto said that Snow planned numerous meetings with members of the Senate and House over the next week to discuss what types of changes the administration favored in the law governing reviews of national security interests when a foreign company purchases a U.S. asset.

He said Snow would also be pushing Congress to pass an increase in the national debt limit before it leaves at the end of this week for a spring recess.

A week ago, Snow sent a letter to congressional leaders warning them that the administration had taken "all prudent and legal actions" to keep from hitting the $8.2 trillion national debt limit and urging prompt action to increase the borrowing limit to avoid the nation's first-ever default on its obligations.

Fratto on Monday refused to provide an exact date when Treasury would run out of bookkeeping options to avoid hitting the limit — other than to say it would occur in mid-March. Congress is scheduled to leave Friday for a weeklong recess.

"We are at the eleventh hour," Fratto said during a briefing at Treasury. "It is vitally important for Congress to act this week."

A default on the debt, a situation where the government misses payments to current bondholders, is a doomsday scenario that has never occurred in the nation's history and is considered highly unlikely this time, given what it would do to the federal government's credit rating.

However, Democrats hope to use the upcoming debate on increasing the debt ceiling by perhaps $781 billion to attack the administration's economic policies.

Fratto said other issues that caused Snow to postpone his trip included discussions with Congress over possible changes in the way an interagency panel reviews foreign takeovers to see if they pose a risk to national security.

The Bush administration was engulfed in protests over the takeover of significant operations at six U.S. ports by a government-owned company from the United Arab Emirates. The company, DP World, announced last week that it would transfer U.S. port operations to an American company to quiet the furor.

DP World has said, however, that the divestiture was "based on an understanding that DP World will not suffer economic loss." Some analysts have suggested that finding a U.S. buyer willing to pay the $700 million that DP World wants might be difficult.

Fratto said the interagency review panel, known as the Committee on Foreign Investments in the United States, was working with the company to get further details on its plans.

As for proposed changes in the law, Fratto said the administration wanted to be sure that any new legislation did not change a climate in the United States that welcomes foreign investment but at the same time reflects the need to protect U.S. security.

"We want CFIUS fully integrated into a post 9-11 environment," he said.