CAMP BASTION, Afghanistan - British Prime Minister Gordon Brown flew to Afghanistan and Pakistan on Monday touting a new security strategy for the region as international alarm spreads over Taliban advances.

This area and the border between Afghanistan and Pakistan is the crucible for global terrorism, Brown told British and allied troops at a base in southern Afghanistan's Helmand province, where Britain has played the leading role fighting the Taliban.

It's important to recognize that if we do not take action and we do not fight back against the Taliban and al Qaeda in Afghanistan and Pakistan, then people in Britain and in other countries represented here are less safe.

British troops in Helmand will be reinforced in coming weeks by the arrival of more than 8,000 U.S. Marines, a massive influx that NATO commanders hope will reverse what they have described as a stalemate in one of the country's most violent provinces.

After meeting Afghan President Hamid Karzai in Kabul, Brown said he would next fly to Pakistan to hold talks with President Asif Ali Zardari.

Asked what Britain would do about instability on the Pakistani side of the border, Brown said: It's clear ... that we cannot sit by and allow this center, or epicenter, of terrorism to continue to exist without taking further action.

Although the Western forces are massing on the Afghan side of the border, attention in Western capitals is increasingly turning across the frontier to Pakistan, where Taliban influence has spread in recent weeks to valleys northwest of the capital.

U.S. Secretary of State Hillary Clinton said on Sunday that Washington was worried about the advancing Taliban seizing control of the Pakistani state, including the keys to the nuclear arsenal of Pakistan.

NUCLEAR WEAPONS SAFE

Zardari told reporters on Monday that Pakistan's nuclear weapons were safe.

Officials traveling with Brown said the new strategy, to be published on Wednesday, will echo a plan unveiled by U.S. President Barack Obama in calling for a focus on fighting al Qaeda and Taliban militants on both sides of the border.

Like Obama's plan, the British strategy will stress the need to train tens of thousands more Afghan soldiers and police to take over responsibility for security from foreign troops.

Unlike Obama, Brown has so far promised few new troops.

Britain has 8,300 soldiers in Afghanistan, the second largest contingent after the United States, and has pledged to send 700 to temporarily boost security for an election in August.

We are confident that we are shouldering our share of the burden, Brown said.

Obama is sending at least 25,000 more U.S. troops this year to join 40,000 Americans and 30,000 other Western soldiers.

The new British strategy document will also call for some of Britain's development aid budget for Pakistan to be diverted to the northern region adjoining Afghanistan. Britain has pledged 665 million pounds ($970 million) to Pakistan and 510 million pounds to Afghanistan in aid over the next four years.

British officials say about two thirds of terrorism plots uncovered in Britain have links to Pakistan. Ten Pakistanis were among a dozen people arrested in Britain on April 8 in what Brown said was an operation against a very big terrorist plot.

All 12 were later released, although 11 have been handed over to immigration officials and face deportation on national security grounds.