The death toll from a double car-bomb attack near the presidential palace in Somalia rose to 20 on Sunday, police said.

On Saturday, police said seven people were killed following two blasts in Mogadishu, which were claimed by the al-Shabab terrorist group. "The number of victims killed in the blasts increased to 20 and more than 40 others have been wounded," said a Somali police official, Ibrahim Mohamed. He said the toll had risen after some of those wounded on Saturday died in hospital. Both civilians and members of the security forces were among the casualties, the official said.

Somali President Mohamed Abdullahi Mohamed condemned the "cowardly attacks." "We will continue defeating terrorists to lead the Somali people to stability and prosperity," he said in a statement.

The first explosion happened at a checkpoint outside the national theater, some 500 meters from the palace on Saturday morning. The second blast, more powerful according to witnesses, came minutes later at a nearby crossroads.

The al-Shabab terrorist group was largely driven out of the capital in 2011 and has lost many of its strongholds. But it retains in control of large rural swathes of the country and continues to wage a guerrilla war against the authorities. The group has vowed to topple the internationally backed government. The worst carnage to date in Somalia occurred on Oct. 14 last year when 512 people were killed in Hodan, a busy commercial district in the capital.