MOGADISHU (Reuters) - Clashes between fighters and Somali troops killed at least 20 people on Saturday including a senior police officer and a foreigner in the heaviest fighting for a week, residents said. Government soldiers battled their way into some rebel strongholds in north Mogadishu where the two sides exchanged mortar and machinegun fire, residents said. The streets are scary and smell of blood today, ambulance driver Ali Musa told Reuters. A senior police officer said that the director of Mogadishus security department was killed in clashes early on Saturday. The govt showed the body of what it said was an Afghani national fighting with Hizbul Islam. He was an Afghani senior commander with the anti-peace men fighting the government. He has his countrys passport, military spokesman Farhan Arsanyo told Reuters. We captured others from Pakistan, Afghanistan and Yemen, and we shall display them soon. Al-Shabaab and allied fighters control swathes of southern and central Somalia and have boxed in government troops and the 4,300-strong African Union force into a few blocks of Mogadishu.