U.S. President George W. Bush ratcheted up pressure on Congress on Thursday to pass new rules for his domestic spying program before it expires this weekend, saying he was prepared to delay a trip to Africa to help advance the measure.

"If we have to delay, we'll delay," Bush said in his latest manoeuvre to prod lawmakers to favour a new law granting legal immunity to telephone companies that cooperated in his warrantless eavesdropping program.

"There really is no excuse for letting this critical legislation expire," he said.

Bush urged the House of Representatives to pass a White House-backed bill approved by the Senate on Tuesday, saying a failure to act would jeopardize national security by undermining intelligence agencies' ability to monitor communications between terrorism suspects.

Democrats, however, accused Bush of fear-mongering as he and his fellow Republicans seem intent on using the spying debate to score points in a presidential election year by painting the Democrats as weak on counterterrorism.

The current legislation expires on Saturday. Bush has vowed to veto any further temporary extensions and is demanding a long-term fix to solidify the government's expanded powers to conduct domestic surveillance without court orders.

Bush was due to fly to Africa on Friday. He said he was prepared to delay his departure "if it will help them complete their work on this critical bill."

'PROTECT THE NATION'

Director of National Intelligence Michael McConnell told the Senate Intelligence Committee that if the law expires "it will do grave damage to our capabilities to protect the nation."

Senate Majority Leader Harry Reid, a Nevada Democrat, wrote Bush a letter accusing him of a "reckless attempt to manufacture a crisis."

House Majority Leader Steny Hoyer, a Maryland Democrat, said the president's comments "implying that any one of us is less focused on the security of our nation were wrong, divisive and harmful."

The House Democrats' chief objection to the Senate bill is that it would grant retroactive immunity to telecommunications companies that cooperated with the program and could now face potentially billions of dollars in civil damages.

About 40 civil lawsuits have been filed accusing AT&T Inc, Verizon Communications Inc and Sprint Nextel Corp of violating Americans' privacy rights by helping the warrantless domestic spying program that Bush authorized shortly after the hijacked airliner attacks in 2001.

Senior Democrats said they planned to explore possible solutions to the stalemate as early as Friday. House Judiciary Committee Chairman John Conyers of Michigan said he was committed to working through the week-long recess that Congress is set to begin at the close of business on Friday.

Hoyer said, however, there was no urgency in passing a new bill without proper review and that even if the current law expired, operations approved under it could continue for a year and others could be approved with a court order.

The 1978 Foreign Intelligence Surveillance Act requires that the government receive the approval of a secret FISA court to conduct surveillance in the United States of suspected foreign enemy targets.

But after the September 11 attacks, Bush authorized warrantless surveillance of contacts between people in the United States and others overseas if one had suspected ties to terrorists.