Three additional suspects have been taken into custody in the investigation of last month's bombing attack at the Boston Marathon, according to the Boston Police Department.

"Three additional suspects taken into custody in marathon bombing case. Details to follow," the police force said in its official Twitter feed on Wednesday, offering no further information on who the suspects were.

They added that there was no threat to the public. 

Three people were killed and more than 260 injured when two bombs exploded near the finish line during the April 15 marathon.

One suspect, Dzhokhar Tsarnaev, is being held over the attack on charges of using a weapon of mass destruction.

His brother Tamerlan, also a suspect, died after a gun battle with authorities when they tried to capture him.

Source: Agencies