At least four people were killed and 10 wounded when a car bomb exploded close to a checkpoint near Somalia's parliament in the capital Mogadishu on Wednesday, police said.A plume of thick black smoke was seen over the city and witnesses said a number of vehicles were on fire.Islamist group Al-Shabaab claimed the attack, after a spike in activity in recent days by the Al-Qaeda linked group which has seen it inflict mass casualties in Somalia and attack a US military base in Kenya."Explosives were packed in a vehicle which the security forces think was trying to pass through the checkpoint but because he could not do that, the suicide bomber detonated it," said police officer Adan Abdullahi."Initial reports we have received indicate four people were killed and more than 10 others were wounded in the blast."Nurses carry a wounded person on a stretcher after a blast near the Somali parliament at the Medina hospital in Mogadishu. (Abdirazak Hussein Farah/AFP).ChaosAbdirahman Mohamed, who was at a nearby grocery store when the blast occurred, said he saw several dead bodies."I saw the dead bodies of several people some of them killed by shrapnel inside their vehicles. There was chaos... and ambulances reached the scene soon after the blast," he said.Shamso Ali, another witness, described "smoke and chaos along the road, the blast was very heavy". "Thanks to God I was a distance away but I saw the smoke and several vehicles caught on fire," he said.Mogadishu is regularly hit by attacks by Al-Shabaab, which has fought for more than a decade to topple the Somali government.The powerful blast comes after Al-Shabaab claimed a massive car bombing in Mogadishu on December 28 that killed 81 people.READ | Five killed in jihadist attack on Somali hotel, al-Shaabab claims responsibilityThe attack hit a busy checkpoint in the southwest of the city, leaving vehicles charred and twisted at a crossroads in the deadliest assault in two years in the Horn of Africa country. Scores more were wounded.Al-Shabaab has also managed to expand its network in the region, especially in Kenya which has suffered several devastating attacks in retaliation for it sending troops into Somalia in 2011. On Sunday, three US citizens died and several aircraft and military vehicles were destroyed when Al-Shabaab stormed a military base in Kenya's coastal Lamu region.ALSO READ | 'Horrendous crime': UN chief condemns deadly Mogadishu attackAlso on Sunday, just hours after the attack, police arrested three men who tried to force their way into a British military training camp in the central Kenyan town of Nanyuki.The Al-Qaeda-linked group has in the past carried out bloody sieges against civilians in Kenya, such as the upmarket Westgate Mall in 2013 and Garissa University in 2015.Ambulances are seen parked in the road at the site where a car bomb exploded near the Somali parliament in Mogadishu. (Abdirazak Hussein Farah/AFP).The uptick in attacks comes almost a year since the January 15 siege on an upscale Nairobi hotel which left 21 people dead.In recent statements, Al-Shabaab has referred to an increase in US military air strikes under President Donald Trump, accusing Washington of killing innocent civilians.