(CNN) -- A car loaded with explosives rocked the Somali capital Wednesday, leaving one injured and damaging a house nearby, authorities said.
The blasts targeted K-4 square, which includes an intersection of roads that connect the airport to the city center.
African Union troops fighting militants in the nation are stationed near the square because of its strategic position, making it a major target in recent years.
Suspects detonated a car parked beside the square, said Mohamed Mohamud Garar, the local government official in charge of security.
Four suspects are in custody, including one caught with a remote control detonator in his hand, he said.
There has been no official claim of responsibility.
Meanwhile, fighter jets bombed Al-Shabaab positions in southern Somalia's lower Jubba province, according to residents.
"It was a huge bombing which lit the whole sky last night and they targeted Al-Shabaab fighters who retreated from Dif,'' said Nur Moalin, a local resident.
Kenyan fighter jets have previously bombed Al-Shabaab targets in southern Somalia.
Al-Shabaab was designated as a foreign terrorist organization by the United States in 2008. It is waging a war against Somalia's government in an effort to implement a stricter form of Islamic law, or sharia.
Somalia has not had a functioning government since 1991.