Two alleged members of Somalia's Shebab militia convicted of murdering a female student were executed by firing squad in the capital Mogadishu on Tuesday, an AFP reporter witnessed.

"These two defendants were found guilty of murdering student Nafiso Ahmed in April," supreme military court chief judge Liban Ali Yarow said.

Unidentified gunmen raided a village near Kenya's restive coastal town of Lamu early Friday, Kenyan officials said, the latest in a string of attacks in the region.

Officials said more than 10 raiders struck at Pandanguo village, about 40 kilometers (25 miles) from Mpeketoni -- where close to 50 people were massacred in an attack last month -- stole guns from police reservists and torched houses and other buildings. 

Somalia's president sacked his security chiefs Wednesday after Islamist Shebab fighters struck the heart of government in an escalating campaign of attacks in the capital and across east Africa.

Al-Qaida-linked Shebab commandos stormed the presidential palace late Tuesday for the second time this year, demonstrating again their ability to infiltrate Mogadishu and hit the most fortified centers of the country's internationally-backed government.

Somalia's Islamist Shebab rebels carried out a major bomb and armed assault against the country's presidential palace late Tuesday, penetrating the heavily-fortified complex before blowing themselves up.

Officials said Somalia's internationally-backed President Hassan Sheikh Mohamud and Prime Minister Abdiweli Sheikh Ahmed were not inside the complex at the time and were "both safe". Security sources said they were with guards from the African Union's 22,000-strong AMISOM force.

Gunmen in Kenya launched two separate attacks, killing one person by hurling a grenade into a restaurant in the restive northeast, and torching conservation offices on the coast near Lamu, police said Tuesday.

At least one person was killed and several injured late Monday in the grenade blast in a restaurant in Kenya's northeastern town of Wajir, before spraying the building with bullets and escaping, police said.

War-torn Somalia is sliding back into an acute hunger crisis with parts of the capital facing emergency levels just short of famine, the United Nations warned Monday.

"Somalia's food security crisis is expected to worsen over the next several months following poor performance of the major rainy season, shrinking humanitarian assistance and access, increasing malnutrition, conflict and surging food prices," the U.N's Food Security and Nutrition Analysis Unit (FSNAU) said Monday.

Several people were killed when a powerful suicide car bomb exploded near Somalia's parliament in the capital Mogadishu on Saturday, police and witnesses said.

Al-Qaida-linked Shebab rebels claimed responsibility for the bombing, the latest in a surge of attacks in Mogadishu during Islam's holy month of Ramadan.

The U.S. military has secretly maintained forces in Somalia since 2007, despite earlier public statements claiming it had no presence in the country until last October, defense officials said Thursday.

The United States has deployed up to 120 troops in the African nation and hopes to bolster its security ties to Somalia's government as it battles al-Qaida-linked Shebab militants, a defense official, who spoke on condition of anonymity, told Agence France Presse.

Somalia's Al-Qaida-linked Shebab claimed responsibility for shooting dead a lawmaker and his bodyguard Thursday, the latest in a surge of attacks in Mogadishu during Islam’s holy month of Ramadan.

"This was a targeted assassination," Shebab spokesman Abdulaziz Abu Musab told AFP.

Famine will break out in war-torn South Sudan within weeks unless massive funding for food aid is provided, aid agencies warned on Thursday.

"If the conflict in South Sudan continues, and more aid cannot be delivered, then by August it is likely that some localised areas of South Sudan will slip into famine," warned Britain's Disasters Emergency Committee (DEC), a coalition of 13 major aid agencies.