A police officer was killed and four others injured in a bomb attack on a convoy of foreign diplomats, Pakistani officials said on Sunday.

The blast from an improvised explosive device (IED) occurred in the northwestern province of Khyber Pakhtunkhwa as the diplomatic convoy was passing through, the Associated Press reported.

The convoy included diplomats from Indonesia, Portugal, Kazakhstan, Bosnia and Herzegovina, Zimbabwe, Rwanda, Turkmenistan, Vietnam, Iran, Russia and Tajikistan, police said in a statement.

All the diplomats escaped the blast unharmed and an investigation has been launched into the incident, it said.