At least 13 civilians were killed in fighting between Somali government forces and hardline Islamist militants in the capital Mogadishu on Monday and bomb blasts killed six people, rescue services and the police said, according to Reuters. The insurgents fired mortars at the city's airport from their stronghold in the crowded Bakara market, triggering return shellfire from African Union (AU) peacekeepers based at and near the airport. "We have so far carried out 13 dead civilians and over 30 who were injured. The death toll is higher and we are busy collecting casualties," ambulance service coordinator Ali Muse told Reuters. The death toll is likely to rise, he said. Police and residents of Somalia's war-weary capital said two remotely controlled roadside bombs aimed at an AU convoy killed four civilians and two police officers. "The first bomb nearly hit the AU's last car. Some policemen and residents ran to the scene, and then the next bomb exploded killing these people," police officer Nur Salad told Reuters. Somalia's fragile government controls just a few blocks in the capital and al Shabaab rebels, who want to impose a harsh version of sharia law on the anarchic nation, control large swathes of southern and central Somalia. The government has said for several months it will launch a major offensive against al Shabaab rebels, who have professed loyalty to al Qaeda, and Hizbul Islam militants. Shells also landed around a strategic road junction known as K4 that links the airport to the residence of President Sheikh Sharif Ahmed. The chaos onshore has allowed pirate gangs to flourish and make millions of dollars from hijacking ships in the Gulf of Aden and the Indian Ocean. Andrew Mwangura, head of the East African Seafarers' Assistance Programme, said the crew of a Saint Vincent and the Grenadines flagged merchant vessel hijacked early on Sunday comprised 11 Indians, 10 Tanzanians, and five Pakistanis.