A suicide bomber wearing an Afghan security uniform detonated his explosives at the entrance to a combined U.S.-Afghan base on Saturday, killing four Afghan soldiers and a civilian, officials said.

The bomber walked up to a security gate for Afghan soldiers outside Forward Operating Base Bermel in the eastern province of Paktika, near the border with Pakistan, NATO's International Security Assistance Force said.

Four Afghan soldiers and a civilian were killed and six Afghans were wounded, NATO's International Security Assistance Force said. No Americans were hurt.

It was not immediately clear if the bomber had been trying to gain entry to the base.

Taliban insurgents have set off more than 100 suicide blasts this year, a record pace, and violence in 2007 has been the deadliest since the 2001 U.S.-led invasion.

More than 5,200 people have died this year due to the insurgency, according to an Associated Press count based on figures from Afghan and Western officials.

Elsewhere, Taliban militants killed three Afghan police who had been trying to prevent them from carrying out a kidnapping, said Helmand provincial police chief Mohammad Hussein Andiwal. The militants successfully kidnapped an Afghan man during the gunbattle, he said.

Separately, U.S.-led coalition forces and Afghan soldiers killed "several" Taliban fighters near the Musa Qala region in Helmand province, the coalition said. Fighting has intensified in recent weeks around Musa Qala — a Taliban-controlled town in the heart of Afghanistan's poppy growing region.

Australia's prime minister, meanwhile, said more NATO powers must directly engage the Taliban to help ease the burden on Australia, the United States, Britain, Canada and the Netherlands, which all have troops in the dangerous southern and central parts of Afghanistan.

Germany, Italy, France and Spain have troops in the relatively safer northern sections, a fact that is causing a rift within NATO, and Australian Prime Minister John Howard said those countries need to help ease the burden on countries operating in the south.

"Some of the other countries have lots of troops in Afghanistan, but they're not in some of the areas that are experiencing the heaviest fighting," he said.

The governments of the Netherlands and Canada, in particular, are coming under domestic pressure to pull out troops because of heavy casualties.

"I think the Dutch government has been very courageous to date," Howard said. "It's not for me to comment on Dutch politics, but I do observe that the Dutch are making a great contribution and as are of course the Canadians."