Forces of al-Shabaab have abandoned the Somali port city of Kismayo, residents and military authorities say, cutting the \"lifeline\" for the extremist group. The militants pulled out of the city about midnight Friday as Kenyan and Somali forces launched a beach assault on the city against fierce resistance from al-Shabaab, the BBC reported. No one is yet in full control of the city. The African Union forces are in control of northern parts of the city and were preparing to move into southern districts, said Kenyan military spokesman Col. Cyrus Oguna. Kismayo residents said al-Shabaab had abandoned checkpoints where they extorted taxes and that the militants were no longer broadcasting on their Andalus radio station, Shabelle Media Network reported. Withdrawal of the militants from Kismayo \"cut the lifeline of al-Shabaab,\" said Kenya\'s Deputy Prime Minister Musalia Mudavadi. \"This is very important because Kismayo has been the port that al-Shabaab have been using to get in the ammunition,\" Mudavadi said. \"It has been the port that has been the center of the piracy menace that we have been experiencing along that coastline for quite some time.\" Kismayo, 310 miles south of Mogadishu, is the second largest city in Somalia.