KABUL, Afghanistan - A roadside bomb blast in eastern Afghanistan killed four American soldiers on Monday, while two NATO soldiers died elsewhere and a battle in the country's poppy-growing heartland killed more than 50 suspected militants.

A woman, a family member of one of the kidnapped South Koreans in Afghanistan, cries as she waits for television news about them in Seoul at around 1300 GMT July 23, 2007. [Reuters]

A purported Taliban spokesman, meanwhile, said the hard-line militia has extended its deadline for the lives of 23 South Korean hostages until Tuesday evening.

The bomb blast came against US soldiers conducting a combat patrol in the eastern province of Paktika, Gov. Mohammad Ekram Akhpelwak said.

Norway said one if its soldiers was killed in Logar province, and NATO said another soldier was killed in the south, though the nationality was not made public.

The six deaths bring to 114 the number of Western soldiers killed in Afghanistan this year, including 54 Americans, according to an Associated Press count.

In Helmand province, the US-led coalition and Afghan soldiers "routed" a large number of Taliban fighters in a two-day battle, killing more than 50 suspected militants, the coalition said.

The battle in Sangin district saw the insurgents attempt to shoot down a coalition aircraft and attack soldiers with a suicide car bomb, the coalition said in a statement. Coalition aircraft dropped four bombs during the engagement, and Afghan forces counted "more than four dozen" insurgents killed, it said.

Coalition and Afghan forces "only engaged legitimate military and enemy targets to minimize the potential of Afghan casualties," said US Maj. Chris Belcher, a coalition spokesman. "We did this even as the insurgents tried to create some propaganda value by placing innocent civilians in harms way."

Civilian casualties have been a major problem for US and NATO forces this year. Taliban militants often fight in populated areas or seek cover in civilian homes, leading to the deaths of ordinary Afghans. There were no immediate reports of civilian casualties during the battle, but those reports sometimes take a day or two to surface.

In Zabul province, meanwhile, Afghanistan's Ministry of Interior said Afghan police forces killed 14 "enemies" during a 12-hour battle Sunday, including a Taliban commander identified as Mohammad Hassan. The ministry said Hassan was the head of administrative affairs during the Taliban's rule.

Qari Yousef Ahmadi, who claims to speak for the Taliban, said the militants extended the deadline another day after the Afghan government refused to release any of the 23 Taliban prisoners the insurgents want freed.

The militants have pushed back their ultimatum on the Koreans' fate at least three times. Afghan officials in Ghazni province have met the militants in person and are also negotiating over the phone, but little progress appears to have been made so far.

"If the government won't accept these conditions, then it's difficult for the Taliban to provide security for these hostages, to provide health facilities and food," Ahmadi told The Associated Press by satellite phone. "The Taliban won't have any option but to kill the hostages."

Though some of Ahmadi's statements turn out to be true, he has also made repeated false claims, calling into question the reliability of his information.

In Washington, State Department spokesman Sean McCormack said the South Koreans "should be released immediately. They pose no threat to anybody. We stand with the South Korean government while they follow this matter closely."

The deputy interior minister, Abdul Khaliq said Afghanistan was not prepared to make a deal "against our national interest and our constitution," though he did not explicitly rule out freeing any prisoners.

Afghan President Hamid Karzai in March authorized the release of five Taliban prisoners in exchange for a kidnapped Italian reporter, but he called the trade a one-time deal. Karzai was also criticized by the United States and European nations who felt the trade would encourage more kidnappings.

Khail Mohammad Husseini, a lawmaker from Ghazni province where the Koreans are being held, said officials had met the kidnappers in person and were also speaking with them by phone.

Meanwhile, Ahmadi said the militants were still holding one German and four Afghan hostages despite the fact that he claimed Saturday they had been shot and killed.

He said the Taliban were demanding the release of 10 Taliban prisoners in exchange for the German and Afghans. Originally there had been five Afghan hostages, but one of them, the brother of Afghanistan's Parliament speaker Arif Noorzai, "escaped" from Taliban custody, Ahmadi said.

Frances Vindrell, the EU representative for Afghanistan, said officials are not convinced the Taliban is actually holding the German and the Afghans. Police have suggested the five might be held by a separate criminal group.

The body of the second German, Ruediger Diedrich, 43, was to be flown back to Germany on Monday, where authorities will carry out an autopsy, the German Foreign Ministry said. His body was discovered riddled with bullet holes, but officials haven't concluded if he died of another cause and was later shot.

The South Korean hostages were kidnapped on Thursday while riding on a bus through Ghazni province on the Kabul to Kandahar highway, Afghanistan's main thoroughfare.