KABUL, Afghanistan (AP) — Gunmen opened fire on a wedding party in eastern Afghanistan, killing nine people, including the groom, officials said Thursday.

The assailants entered a field where the groom and his family had gathered Wednesday night in the remote Dur Baba district and started shooting, said Ahmad Zia Abdulzai, the provincial government spokesman. The attackers also set fire to a nearby house and a car.

No one immediately claimed responsibility for the attack, which occurred on the eve of a NATO meeting in Brussels to discuss the alliance’s mission in Afghanistan. President Barack Obama is expected to announce soon how many troops he will cut from the 100,000-strong U.S. force in Afghanistan in July, leading to fears that other NATO allies involved in the fight against Taliban insurgents may follow suit.

U.S. Defense Secretary Robert Gates said Thursday in Brussels that there will be no “rush for the exits” by the United States. Germany has warned that pulling too many Americans out of the 10-year war could risk NATO’s strategy.

The cousin of the groom killed in Wednesday’s attack is the chief administrator for Dur Baba district, suggesting the shooting may have been an insurgent strike against the family for being allied with the government. Officials are investigating, Abdulzai said.

The Taliban and other allied groups have regularly targeted both government officials and those seen as in league with the Afghan administration or international forces. The insurgents have said they do not consider these people civilians.

The assailants briefly held one of the attendees, saying he was an American spy, said the district administrator, Hamisha Gul. Gul said he was not at the gathering but had spoken to family members.

Among the dead were the groom, his father and one of his brothers, Gul said. He said about 20 men had gathered to celebrate and organize the wedding ceremony, which was scheduled for Thursday.

On Thursday, villagers laid out the bodies of the dead, covered in white sheets for a funeral service.

Civilian casualties have risen sharply because of an increase in insurgent attacks in recent years. In 2010, at least 2,777 civilians were killed in Afghanistan, a 15 percent increase over the previous year, according to the United Nations. The increase was attributed entirely to insurgent attacks.

Afghan and international forces also continue to record more casualties. On Thursday, two NATO service members were killed in bomb attacks in the south, the coalition said. The latest deaths make 19 international troops killed so far this month.

Fighting typically rises in the warmer months in Afghanistan. June 2010 was the deadliest month of the war for the country’s military allies, with 103 international troops killed.

In Brussels, Gates sought to ease concerns about the troop cut at a meeting of defense ministers at the alliance’s headquarters.

“Even as the United States begins to draw down next month, I assured my fellow ministers that there will be no rush to the exits on our part and we expect the same from our allies,” Gates told reporters.

NATO Secretary-General Anders Fogh Rasmussen said he was confident the U.S. troop withdrawals will not affect security Afghanistan.