ISLAMABAD, Pakistan

At least two Pakistani citizens were killed in a suicide bombing in Pakistan's southern port city of Karachi while five Japanese nationals escaped unharmed, and two of the attackers were also killed, officials said on Friday.

"All five Japanese nationals are safe," local daily Dawn quoted police official Asif Aijaz Shaikh as saying after the bombers targeted a van carrying Japanese citizens in the city’s Landhi area.

Shaikh, the deputy inspector general of the Counter-Terrorism Department, also confirmed that another "backup" suicide bomber was killed by police.

The Japanese nationals were on their way to the export processing zone of the port city when a motorcycle-riding suicide bomber rammed into their car.

Two security guards were injured in the attack and taken to the hospital.

No group has yet claimed responsibility for the attack.

In a statement, Pakistan’s Foreign Ministry confirmed the death of two Pakistani nationals and said five Japanese nationals remained unhurt while timely action by law enforcement agencies resulted in the death of two terrorists.

"The Government of Pakistan strongly condemns this heinous act of terrorism. All necessary measures will be taken to bring the perpetrators to justice. Such dastardly acts only strengthen the resolve of the Government and the people of Pakistan to eliminate the scourge of terrorism," said the ministry.

The ministry stressed that Islamabad is committed to ensure the safety of foreign nationals living in the country.

Last month, five Chinese nationals working on the Dasu Hydropower Project in the remote Kohistan district were killed in a suicide attack in the Shangla district of the northwestern Khyber Pakhtunkhwa province. Their Pakistani driver was also killed in the attack.

The hydropower project is part of the China-Pakistan Economic Corridor (CPEC), a $65 billion project set to connect China's northwestern Xinjiang province to the port of Gwadar in Pakistan's Balochistan province.