At least 11 people, most of them children, were killed in a series of explosions at an Afghan gas storage facility, which triggered a massive inferno in a nearby settlement for displaced people, officials said Tuesday.

It was not immediately clear whether the blasts late Monday on the edge of the relatively peaceful western city of Herat were the result of an accident or caused by a militant attack.

At least 11 Afghan soldiers have been killed in a Taliban ambush in western Afghanistan, officials said Monday, as troops face their first fighting season without NATO combat support.

The militants launched their annual spring-summer offensive in late April, vowing nationwide attacks in what is expected to be the bloodiest summer for a decade.

At least four Afghans were killed Friday in a Taliban suicide attack on the U.S. consulate in the Afghan city of Herat, the State Department said Friday.

There were no U.S. casualties in the attack on Herat, a key business hub located in western Afghanistan near the border with Iran, deputy State Department spokeswoman Marie Harf told reporters.

Seven heavily armed Taliban suicide attackers struck the U.S. consulate in the Afghan city of Herat before dawn on Friday, setting off two car bombs and sparking a shootout with U.S. forces.

The sophisticated attack in the western city, a key business hub near the Iranian border, underscored how the Taliban are able to strike outside their main centers in the south and east.

Iran has temporarily shut its consulate in the Afghan city of Herat after protesters there attacked the mission's compound, the official IRNA news agency reported Tuesday quoting a foreign ministry source.

"Iran's consulate in Herat is closed until further notice," an informed source in the ministry was quoted as saying.

A bomb exploded Saturday in a bazaar in western Afghanistan crowded with people shopping to celebrate the end of the Muslim holy month of Ramadan, killing four civilians, an official said.

A dozen other people were wounded by the bomb which was placed under a bridge in Shindand district of Herat province, provincial spokesman Mohiuddin Noori told AFP.