BAGHDAD: A volley of rockets slammed into an Iraqi airbase north of Baghdad where US forces have been based, wounding four local troops, the Iraqi military said on Sunday. Its statement said eight Katyusha-type rockets landed on Al-Balad airbase, wounding two Iraqi officers and two airmen. Al-Balad is the main airbase for Iraq’s F-16s, which it bought from the US to upgrade its air capacities. The base had held a small US Air Force contingent as well as American contractors, but a majority had been evacuated following tensions between the US and Iran over the past two weeks, military sources told. “About 90 per cent of the US advisers, and employees of Sallyport and Lockheed Martin who are specialised in aircraft maintenance, have withdrawn to Taji and Erbil after threats,” one of the sources said.