LONDON (Reuters) - Republican presidential candidate Rudy Giuliani urged NATO to admit Australia, India, Israel, Japan and Singapore on Wednesday as part of proposals to combat Islamic extremism.

Speaking to a U.S.-British conservative group in London, Giuliani said Britain and the United States must stand side-by-side in tackling Islamic terrorism.

“This is no time for defeatism and appeasement,” he said.

He also ruled out a “pre-determined timetable” for a U.S. pullout from Iraq and said British Prime Minister Gordon Brown was right to reject such a timetable for British forces.

Victory there should depend on reaching a point at which Iraq could be maintained as a U.S. ally “in the terrorist war against us”, said Giuliani, Republican frontrunner in the race to succeed George W. Bush in the November 2008 election.

Iraq was part of a much larger war, Giuliani said, urging Washington and London not to be distracted from Afghanistan, where he called for a redoubling of efforts.

Among his proposals for the United States and Britain to take the lead in “winning this war”, Giuliani urged the two countries to push for an expansion of NATO into a global body.

“We should open the organization’s membership to any willing state that meets basic standards of good governance, military readiness (and) global responsibility, regardless of location,” he said.

“I think we should consider countries such as Australia, Singapore, India, Israel, Japan ... and there are probably a whole group of others that we could put on that list,” he said.

The defense alliance has expanded in recent years but its current membership is 26 countries in North America and Europe.

CALL FOR EXPANDED U.S. MILITARY

Facing increasing war-weariness in the United States, Bush last week ordered gradual troop reductions in Iraq but defied calls for a dramatic change of course.

Giuliani, giving the first “Margaret Thatcher Atlantic Bridge” lecture to an audience that included the former British prime minister, called for an expansion of the U.S. military, saying it had cut back too much after the Cold War.

“We need to add at least 10 new combat brigades, that’s probably just the beginning,” Giuliani said, adding the United States faced not only Islamic terrorism, but also had to consider the possibility of a “large war with a nation state”.

Speaking earlier, Giuliani said the United States should spell out clearly to Iran that it would not allow Tehran to acquire nuclear weapons. Giuliani said he had discussed Iran with Brown, his predecessor Tony Blair and Israeli Prime Minister Ehud Olmert in the past few days.

The West suspects Iran is developing atomic weapons but Tehran says its nuclear program is aimed solely at generating electric power.

“The policy of the United States of America should be very, very clear: we will use any option we believe is in our best interest to stop them from being a nuclear power,” Giuliani said.