At least 14 people were killed on Sunday in an attack by the Islamic State (IS) militant group at a gas plant near Baghdad, Iraqi officials said.At least 21 people were injured as three car bombs exploded at the gate of gas plant in Taji, BBC reported.As many as six men wearing explosive belts rushed in and blew up gas tanks, before security forces won back the facility.IS, which controls large parts of western and northern Iraq, has stepped up attacks in Baghdad recently. The group claimed responsibility for the Sunday's attack.Those killed in the blasts included workers and members of the security forces.BBC Arab affairs analyst Sebastian Usher said that although IS has suffered recent setbacks in both Iraq and Syria, such an elaborate attack close to Baghdad underlines the threat the group still poses.It comes four days after car bomb attacks by IS killed 93 people in Baghdad on Wednesday -- the deadliest day of violence in the capital so far this year.Meanwhile, Iraq remains in political crisis.Divisions among political factions has prevented the formation of a new cabinet. The deadlock has raised concerns about the government's ability to fight IS.