Gunmen launched multiple attacks in the Afghan capital Kabul on Sunday, assaulting Western embassies in the heavily guarded, central diplomatic area and at the parliament in the west, witnesses and officials said.

The Taliban claimed responsibility, saying their main targets were the German and British embassies and the headquarters of Afghanistan's NATO-led force.

Taliban fighers had also launched assaults in two provinces, a spokesman for the insurgents said.

We claim responsibility for these attacks, said Taliban spokesman Zabihullah Mujahid.

Attackers fired a rocket-propelled grenade into a house used by British diplomats in the city centre and smoke billowed from the building after the blast, a Reuters witness said.

Two rockets hit a British Embassy guard tower near the Reuters office in the city.

Three others hit a supermarket near the German Embassy popular with foreigners, Reuters witnesses said. Women scurried for cover as crackling gunfire was heard above.

As the gunfire continued, U.S. army convoys could be seen coming to the area accompanied by Afghan police in flak jackets.

There was no word on any casualties.

The coordinated attack is bound to intensify worry in the run-up to the planned withdrawal of foreign combat troops by the end of 2014.

Afghan security forces, who are responsible for the safety of the capital, were scrambling to reinforce areas around the so-called green diplomatic section of the city centre.

Gunfire came from various directions in the area, close to both the U.S. and British embassies, while smoke billowed from the nearby German embassy, the Reuters witnesses said.

Embassy alarms were sounding. Staff at the embassies were not available for comment.

Attackers also fired rockets at the parliament building, in the west of the city, and at the Russian embassy, a spokesman for the parliament said.

Afghan media said insurgents had stormed the Star Hotel complex near the presidential palace and the Iranian embassy and black smoke was pouring from the building.

(Reporting by Amie Ferris-Rotman, Rob Taylor and Jack Kimball; Writing by Robert Birsel; Editing by Raju Gopalakrishnan)