At least 18 people were killed and 57 wounded in fighting in the Somali capital of Mogadishu as the government marked National Army Day on Monday, a medical official said.

Two children, ages 4 and 6, were among those killed in the shelling, and others as young as 4 were wounded, said Ali Muse, who runs Mogadishu’s ambulance service. Two of the dead were killed by a roadside bomb targeting the military, he said.

The shelling hit most of the city, starting when mortars fired from militant positions hit the presidential palace and the airport during events commemorating National Army Day, Muse told CNN.

Addressing the Somali army inside the presidential palace, President Shiekh Sharif said, “You have responsibilities to fulfill as the national army to liberate the country from the foreign militants who invaded the country, and these foreign militants are aiding Al-Shabaab.”

The president also promised the army better pay and training.

Gen. Mohamed Gelle Kaahiye pledged to the president that “the armed forces are ready to terminate the foreign militants and those who are giving them shelter … We will restore the dignity of the Somali nation and retake control of the areas where the insurgents are now.”

Al-Shabaab, a group with ties to al Qaeda, is considered a terrorist organization by the United States, which blames it for shootings and suicide bombings inside Somalia.

The group has also threatened African neighbors, including Ethiopia, Djibouti, Kenya, Eritrea, Ghana, Sudan and Uganda.