Explosions rocked two of Somalia's largest cities on Saturday as officials said a suicide car bomber detonated near the port in Mogadishu and a land mine in a restaurant on the outskirts of Baidoa killed four people. Ali Abdullahi, an official with the Southwestern regional state, said the mine was detonated by remote control as people were dining during the morning rush. Several others were wounded, he said. There was no immediate claim of responsibility, but the Al Qaeda-linked Al Shabab group has targeted the cities in the past. In Mogadishu, thick smoke billowed over the port area after police Col. Ahmed Ali said the car bomber detonated near the gates of the motor vehicle imports duty authority headquarters. At least seven people were wounded on Saturday as police shot a suicide car bomber at a checkpoint outside the port in Somalia's capital Mogadishu, police and witnesses said. "A suicide bomber tried to strike the police post in front of the port but the security forces shot him and the vehicle exploded," said police officer Abdukadir Ahmed. "Two police officers and five civilians were wounded," he said. The car bomber sped through the first security checkpoint before police officers opened fire at the vehicle which exploded outside the gates, Ismail Mukhtar, spokesman for Somalia's information ministry, said. He confirmed that people were injured. "Metal debris fell all over us inside the port and we heard gunfire," said a port worker who sought anonymity for security reasons. "Security forces have surrounded the area." The blast shoook the ground, said Mohammed Ali, a shopkeeper in the area. At the city's Madina hospital, a nurse, Halima Nur, said it had received five people injured in the blast for treatment. Somalia has been mired in conflict since 1991, when clan warlords overthrew dictator Siad Barre and then turned on each other. Since 2008, the militant group Al Shabab has been fighting to overthrow the central government and establish its rule based on its own harsh interpretation of Islam's sharia law.