KABUL, Afghanistan -- A total of six U.S. troops have died in the latest attacks in Afghanistan's embattled southern and eastern regions, NATO said Sunday.

One serviceman died in a bombing on Sunday in southern Afghanistan, while two others were killed in a bomb attack in the south on Saturday and three in fighting in the east the same day, NATO said. Their identities and other details were being withheld until relatives could be notified.

The latest deaths bring to 41 the number of American forces who have died this month in Afghanistan after July's high of 66. A total of 61 international forces have died in the country this month, including seven British troops.

Fighting is intensifying with the addition of 30,000 U.S. troops to bring the total number of international forces in Afghanistan to 120,000 - 100,000 of them American. Most of those new troops have been assigned to the southern insurgent strongholds of Helmand and Kandahar provinces where major battles are fought almost daily as part of a gathering drive to push out the Taliban.

NATO said eight insurgents were killed in joint Afghan-NATO operations Saturday night in the province of Paktiya, including a Taliban commander, Naman, accused of coordinating roadside bomb attacks and the movement of ammunition, supplies and fighters.

Automatic weapons, grenades, magazines and bomb-making material were found in buildings in Zormat district along the mountainous border with Pakistan. Afghan leaders frequently complain that Pakistan is doing to little to prevent cross-border incursions and shut down insurgent safe havens in its territory.

Just south in Khost province, U.S. and Afghan troops fought back simultaneous attacks Saturday by around 50 insurgents wearing American uniforms and suicide vests on a pair of bases, including one where seven CIA employees died in a suicide attack last year.

The morning raids appeared to be part of an insurgent strategy to step up attacks in widely scattered parts of the country as the U.S. focuses its resources on the battle around Kandahar.

The assault in the border province of Khost began about 4 a.m. when dozens of insurgents stormed Forward Operating Base Salerno and nearby Camp Chapman with mortars, rocket-propelled grenades and automatic weapons, according to NATO and Afghan police.

Two attackers managed to breach the wire protecting Salerno but were killed before they could advance far onto the base, NATO said. Twenty-one attackers were killed - 15 at Salerno and six at Chapman - and five were captured, it said. Chapman was where the CIA employees were killed Dec. 30 in a suicide attack.

The Afghan Defense Ministry said two Afghan soldiers were killed and three wounded in the fighting. Four U.S. troops were wounded, NATO officials said.

U.S. and Afghan officials blamed the attack on the Haqqani network, a Pakistan-based faction of the Taliban with close ties to al-Qaida.

Also Saturday, a candidate running for a seat in parliament from Herat province in northwestern Afghanistan was shot and killed on his way to a mosque, said Lal Mohammad Omarzai, deputy governor of Shindand district. He said two men on a motorbike opened fire on Abdul Manan, a candidate in the Sept. 18 balloting. He later died of his wounds.

That followed the kidnapping Wednesday of 10 aides to candidate Fawzya Galani, also in Herat. Villagers said armed men stopped the two-vehicle convoy and drove off in them. It wasn't clear whether the kidnappers were insurgents, criminals, or working for a political rival.

NATO has stepped up efforts to provide security to alllow an election whose outcome will be generally accepted as credible.

Yet frictions have continued to mar the relationship between the government of Hamid Karzai and its international partners, largely over the knotty question of endemic official corruption.

On Saturday, the government criticized U.S. media reports that alleged numerous Afghan officials had received payments from the CIA - including one who allegedly took a bribe to block a wide-ranging probe into graft.

A presidential office statement did not address or deny any specific allegations, but called the reports an insult to the government and an attempt to defame people within it.

The statement came the same day as a top graft-battling Afghan prosecutor said he had been forced into retirement.

Deputy Attorney General Fazel Ahmed Faqiryar has complained that the attorney general and others are blocking corruption cases against high-ranking government officials. He said his boss, Attorney General Mohammad Ishaq Aloko, wrote a retirement letter for him earlier this week and that President Hamid Karzai accepted it.