NAIROBI, Kenya — The Kenyan military says its jets have bombed an airport in Somalia — the last major city in the country held by extremist insurgents who are fighting African Union troops.

Kenya's military said Tuesday that its bombing of the Somali port city of Kismayo destroyed a warehouse and armory belonging to the Islamist militant group al-Shabab, which controls the city. Al-Shabab said on Twitter, however, that the three bombs which hit the airport didn't cause any casualties or losses.

Claims about fighting in Somalia are difficult to verify.

Kismayo is the main remaining stronghold of the al-Qaida-linked al-Shabab. The group, considered terrorists by the United States and others, is waging an insurgency against the U.N.-backed Somali government, which is being bolstered by African troops including forces from Kenya.