The NATO-led International Security Assistance Force (ISAF) said an American service member was killed in an insurgent attack in the east on Sunday.

There has been a sharp increase in foreign military deaths, many of them American, as foreign troops launch more operations to counter a growing Taliban-led insurgency that has spread out of traditional strongholds in the south and east.

At least five ISAF troops have been killed since Friday, including the first Georgian.

Civilian casualties, a point of great tension between Afghan officials and Washington over the past year, have also reached record levels.

Violence across Afghanistan has hit its worst since the Taliban were ousted by U.S.-backed Afghan forces in late 2001.

The spiraling death tolls come despite the presence of almost 150,000 foreign troops in Afghanistan and will be another worrying statistic when U.S. President Barack Obama conducts a strategy review of the war in December.

Public support for the war is flagging, with a recent opinion poll by NBC television and the Wall Street Journal showing as many as seven in 10 Americans saying they did not believe the war would end successfully.

The traditional summer fighting period has taken a heavy toll on foreign troops this year. A total of 102 were killed in June, the deadliest month of the war, followed by 88 in July and another 80 in August, according to independent monitor www.iCasualties.org.

The latest casualties take to 2,068 the number killed since 2001, almost half of them in 2009 and 2010. Roughly 60 percent of those killed were Americans. U.S. and other NATO commanders have warned of more tough fighting ahead.

Also on Monday, ISAF said investigations into an attack in southern Helmand province last Wednesday showed that four civilians were inadvertently killed and two wounded by an ISAF strike after a patrol came under fire by insurgents.

"We regret the loss of life and injuries to our civilian partners," U.S. Air Force Brigadier General Timothy Zadalis said.

Last Thursday, Afghan President Hamid Karzai strongly condemned an ISAF air strike in northern Takhar province which he said killed 10 election campaign workers and wounded a candidate for the September 18 parliamentary elections.

ISAF commanders, however, maintain the strike killed a senior member of the al Qaeda-linked Islamic Movement of Uzbekistan.

A United Nations report released last month showed that civilian casualties had risen by 31 percent in the first six months of 2010, compared with the same period last year. More than three-quarters of the casualties were caused by insurgents.

(Reporting by Paul Tait; Editing by David Fox)

With the poll less than two weeks away, the U.N.-backed Electoral Complaints Commission said it has already received 1,503 complaints, ranging from public resources being given to preferred candidates to interference by government officials.

Early signs for a smooth and fair process are not promising.

"Things are getting worse. Many (politicians) are just after making themselves rich and working for their own interests," said Azizullah, a 32-year-old Kabul civil servant.

"I do not want to vote, because I have lost my trust in the government, parliament and election under the current situation," he said.

The election is a litmus test of stability in Afghanistan before U.S. President Barack Obama conducts a war strategy review in December that will examine the pace and scale of U.S. troop withdrawals from July 2011.

Graft and cronyism are major concerns ahead of the vote after last year's fraud-marred presidential election in which a third of the votes for President Hamid Karzai were tossed out as fake.

According to the government-appointed Independent Election Commission, preliminary results should be available four days after the vote but final results may not be out until October 31.

Those dates depend on the number of complaints received, which promises to be high given the number already lodged and that 2,500 candidates are vying for 249 seats in the Wolesi Jirga, or lower house of parliament.

WARLORDS, MILITIAS

Seventy-six candidates have already been disqualified, according to the IEC, for offences ranging from improper registration to links with warlords and private militias.

"The parliamentary elections (have) to be a step forward, and my fear is that we might miss this opportunity once again, and it might turn into a curse," former foreign minister Abdullah Abdullah said on Sunday.

At about the same time Abdullah was speaking, the Taliban further clouded an already grim picture by issuing its first explicit threat to disrupt the poll, vowing to target foreign troops and then Afghans who take part.

At least four candidates have been killed so far, according to the United Nations and government officials, and dozens of campaign workers wounded. Some of the attacks have been blamed on the Taliban and other insurgents.

The Taliban mounted about 130 attacks against last year's election. While failing to disrupt the process significantly in much of the country, but voter turnout was low in the ethnic Pashtun south, where the Taliban are strongest.

The threat of poor security has already forced the IEC to close 938 out of 6,835 polling centers across the country, potentially disenfranchising thousands of Afghans even though they will be able to vote in other centers.

There are almost 150,000 foreign troops in Afghanistan but they will play a background role during the election, with security to be provided by Afghan police and soldiers.

Still, violence is at its worst since the Taliban were ousted by U.S.-backed Afghan forces in late 2001, with military and civilian casualties at record levels.

Despite the threats, Abdullah urged Afghans to vote.

"Giving up on the democratic process will not get us anywhere, and the international community will not achieve any of their goals," he said.

(Additional reporting by Sayed Salahuddin; Editing by Paul Tait and David Fox)