Britain's foreign secretary held talks Thursday with Prime Minister Nouri al-Maliki as at least 13 people were reported killed in the ongoing fighting between Shiite militiamen and Iraqi and US-led forces. The British Embassy confirmed that Foreign Secretary David Miliband had arrived on a previously unannounced visit but refused to release any other information due to security concerns. Britain has around 4,500 troops in Iraq, most of them based at an airport camp near the southern city of Basra. Britain suspended plans to withdraw about 1,500 troops this spring after fighting broke out last month between Iraqi forces and Shiite militiamen. In the latest clashes, five people died and 28 were wounded early Thursday in Baghdad's embattled Sadr City district, a stronghold of the Mahdi Army militia of anti-American cleric Muqtada al-Sadr. The figures came from a police officer who asked not to be identified because he was not authorized to speak to the media. Another eight people were killed and two wounded during fighting in the capital's Husseiniyah area, another base of Shiite militants. The figures came from a hospital official who spoke on condition of anonymity out of safety concerns.