Four Indian citizens have been kidnapped in war-torn Libya, reportedly by the Islamic State extremist group, TV reports said.

The citizens, all university teachers, were kidnapped from Sirte town near Tripoli on the evening of Thursday, July 30.

They had been teaching at the university for a year, NDTV reported while quoting the ministry of external affairs.

"No ransom demand has been made yet. We are trying to ascertain their whereabouts," foreign ministry officials said.

According to the report, the area from where the Indians were kidnapped is under the control of the Islamic State, which has seized large swathes of Iraq and Syria and has declared itself a caliphate.

The kidnapping comes almost a year after the Indian government had issued an advisory asking its citizens to leave conflict-hit Libya.