The foreign bombers -- one of them as young as 20 -- were equipped with suicide vests and one of them blew herself up after being cornered in a firefight, police said.
The city police chief told the media that the five people riding in a car had explosive devices strapped around their waists and were apparently out to launch a terror attack in the Balochistan capital.
"They were first ordered to stop for a snap check near the airport but raced away and were than intercepted at the Frontier Constabulary checkpost in Kharotabad," he said.
The police official said when asked to get out of the car the suspected bombers started a gun battle with security personal and on being corned one of the female bomber`s blew herself up.
"One of the suicide bombers is a 25 to 27 year old woman while another one is a young girl of around 20-years," he said.
"We are investigating but so far it appears from documents found on them all five belonged to Chechnya," he said.
He said the security forces had suffered no casualties and only one policeman was wounded and taken to hospital for treatment.
"We are trying to find what their intentions and target were but apparently they were out to commit a terrorist attack in the city," he said.
The banned Tehreek-e-Taliban and al Qaeda have vowed to seek revenge and step up suicide attacks in Pakistan after the US Navy SEALs killed Osama bin Laden in a late night raid at his hideout in Abbotabad on May 2.
A Saudi Consulate diplomat was yesterday shot dead by persons on two motorcycles in Karachi but the TTP later claimed it had nothing to do with the attack.
Police are still investigating whether the shooting of the Saudi diplomat, Hassan Khatani, who was also a security officer of the Saudi consulate in Karachi is related to bin Laden`s death.
The body of the diplomat was flown to Jeddah on Tuesday.