First explosion took place at a checkpoint near the national theatre causing widespread destruction.

The death toll from a double car bomb attack near the presidential palace in Somalia’s capital, Mogadishu, has risen to 20, police said.

Police on Saturday had said seven people were killed following the two explosions, claimed by the al-Qaeda-linked al-Shabab group, which often targets Mogadishu.

“The number of victims who were 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 from the security forces were among the casualties, the official said.

Somali President Mohamed Abdullahi Mohamed condemned the “cowardly attacks”.

“We will continue defeating terrorists in order to lead the Somali people to stability and prosperity,” he said in a statement.

The first car bomb had detonated at a checkpoint near the national theatre, sending thick white smoke billowing into the sky.

The second explosion took place just minutes after, reportedly in the same area.

Those killed include soldiers as well as three staffers from the London-based Universal TV station, said police Captain Mohamed Hussein. A prominent journalist, Awil Dahir Salad, was among the fatalities, he added.

Ahmed Abdi, another police officer, said the first car bomb exploded at a checkpoint some 400 metres from the president’s residence.

Police said politicians and other officials had been travelling nearby on what is a business day in the Horn of Africa nation.

Mohamed Bulbul, a journalist based in Mogadishu, told Al Jazeera that Mohamed Tulah, the deputy governor for security in Somalia’s Benadir region, was wounded in the first blast.

“Government officials are stationed near the area and it is a very guarded place. From what we know, the security bomber hit the security checkpoint,” he said.

Images circulating on social media showed destroyed vehicles and debris littering the streets.

“At first I saw a vehicle driving to and fro, then we tried to stop people walking here and there, and then in the blink of an eye the vehicle exploded, causing havoc,” traffic police officer Mohamed Harun told The Associated Press.

BREAKING: Heavy explosion heard in #Mogadishu #Somalia pic.twitter.com/Ddt5TfKCiJ

Al-Shabab, which has carried out several attacks in Somalia and neighbouring countries, is fighting to topple the Somali government and wants to impose a strict version of Islamic law in the Horn of Africa country.

The group used to control most parts of the country, but since 2010, the fighters have been removed from most major towns and cities.

The US military, which partners with Somali forces and a 20,000-strong African Union peacekeeping mission, has increased air attacks against al-Shabab under the Trump administration. At least 47 US strikes have been carried out this year.