MOGADISHU, Somalia (AP) — Somalia's new president on Thursday declared the country a war zone and replaced its military and intelligence chiefs while instructing the army to prepare a new offensive against al-Shabab extremists.

The shakeup is an attempt to improve the worsening security situation as the al-Qaida-linked al-Shabab steps up its deadly bombings in the capital since President Mohamed Abdullahi Mohamed was elected in February. A car bomb blast on Wednesday at a Mogadishu restaurant killed at least seven people.

The Somali-American president wore a military uniform as he declared a "new offensive against terrorist groups." He gave extremists a 60-day amnesty to surrender.

The declaration comes roughly a week after the Trump administration approved greater U.S. military authority to pursue al-Shabab in Somalia, including more aggressive airstrikes as parts of southern Somalia will be considered areas of active hostilities.

Thursday's announcement is seen as an attempt by Mohamed to consolidate power in this long-chaotic horn of Africa nation. He also replaced the country's police chief and Mogadishu's mayor.

Al-Shabab has denounced the new president as an "apostate" and warned Somalis against supporting him. The group has been pushed out of the capital and other major urban areas in Somalia by national and African Union multinational forces, but it continues to carry out deadly bombings and attacks in Mogadishu and elsewhere. Targets have included hotels, military checkpoints and the presidential palace.

The extremist group is just one of the challenges facing the new government, which despite hundreds of millions of dollars of support from the international community still struggles to expand its authority beyond the capital and other selected areas.

Drought threatens about half of Somalia's population of 12 million, the United Nations has said, and hijackings of cargo ships off the country's coast in recent weeks have signaled a return to piracy on one of the world's most critical shipping routes. Somalia also is called the world's most corrupt nation by Transparency International.

Mohamed Ahmed Jimale was named the new chief of defense forces of the Somali National Army, replacing Maj. Gen. Mohamed Adan Ahmed. Abdullahi Mohamed Ali was appointed as the national intelligence agency chief, replacing Abdullahi Mohamud Gafow. Ali has held the position in the past. Gen. Abdihakim Said was appointed as police chief, replacing Gen. Mohamed Sheikh Hassan.