KABUL, Afghanistan — An explosion in the Afghan capital on Thursday killed two lecturers at the Kabul University, after a bomb attached to the car they were traveling in went off, a police spokesman said.

The attack took place around noon near the university, said Kabul police spokesman Ferdaws Faramarz. No group immediately claimed responsibility for the bombing.

The two lecturers, Mubasher Muslimyar and Marouf Rasikh, taught at the university's Islamic studies faculty, according to an Afghan official who spoke on condition of anonymity because he was not authorized to talk to the media.

Two years ago, Muslimyar had been briefly arrested by the Afghan intelligence agency over allegations of promoting militant propaganda by the Islamic State group among university students. No charges were raised and he was later released.

Kabul police said an investigation team had arrived at the scene of the explosion. This was the second explosion on Thursday in Kabul. An earlier one had targeted police in the District 10 area of Kabul but caused no casualties.

Afghanistan has seen a nationwide spike in bombings, targeted killings, and violence on the battlefield as peace negotiations in Qatar between the Taliban and the Afghan government have stalled.

The Islamic State group's local affiliate has claimed responsibility for some of the attacks, but many go unclaimed, with the government putting the blame on the Taliban. The insurgents have denied responsibility for most of the attacks.