Taliban suicide bombers and gunmen attacked a foreign guesthouse near parliament in the Afghan capital Saturday, the latest assault targeting foreigners as NATO troops withdraw from the country, witnesses and police said. It wasn't immediately clear if there were casualties.

Police and intelligence officers quickly surrounded the scene of the attack, a guesthouse home to Europeans working for the Afghan government, witness Samir Noorzai said.

"There were suicide bombers entering the guesthouse," said Noorzai, who works near the guesthouse. "There was some gunfire, grenades and explosions."

Police spokesman Hashmat Stanikzai confirmed the ongoing attack on the guesthouse, but declined to comment further.

The Taliban said in a statement that it had launched the suicide attack on "a secret missionary center" in the city's west. The militants have waged a series of large-scale attacks on Kabul in recent days, including an assault in the upscale Wazir Akbar Khan district home to embassies and international agencies and the suicide bombing of a British embassy vehicle. There have been about a dozen attacks in the past two weeks alone.

Violence rages on outside of Kabul as well as U.S. and NATO troops are set to officially conclude their combat role in the country at the end of the year. On Saturday, Taliban attacks killed at least 11 Afghan soldiers in southern Helmand province, including one on a base once held by NATO forces, said Omar Zwak, spokesman for the provincial governor.

The Taliban has been launching assaults since Thursday on the base, once known as Camp Bastion until the British handed it over last month. Camp Bastion also once held Camp Leatherneck, a U.S. Marine base in the volatile southern province.

Zwak said the Bastion attack killed at least six Afghan soldiers and 20 Taliban fighters and wounded 10 Afghan soldiers. The other attack, a suicide bombing targeting a military base in the province's Sangin district, killed five soldiers and wounded seven, he said.