Explosion, gunfire heard in diplomatic quarter of Afghan capital KABUL (Reuters) - An explosion shook houses in the diplomatic quarter of the Afghan capital on Thursday evening and was followed by heavy gunfire that could still be heard an hour later, according to Reuters witnesses and security officials. The blast was caused by a car bomb, according to a military commander, who said the target was a foreign guesthouse in the Wazir Akbar Khan area, where many embassies and international organizations are located. Two or three insurgents have entered the compound. Our forces are there and the fight is ongoing," the commander of 111 Military Corps Kabul, Qadam Shah Shaheem, said. The explosion follows an attack earlier in the day on a British embassy vehicle that killed five people including one British citizen. A spokesman for the police confirmed the later attack had targeted a foreign guesthouse but gave no further details. The Taliban swiftly claimed responsibility for the blast, saying their fighters had targeted an "important center of the enemy." Reporting by Jessica Donati and Mirwais Harooni; Editing by Hugh Lawson