Members of the Iraqi security forces take part in an intensive security deployment in the city of Baquba. REUTERS/Stringer

New Delhi - India announced it would stop granting its nationals permission to travel to Iraq for work on Friday as it stepped up efforts to secure the release of 39 Indians abducted by gunmen.

“The overseas affairs ministry has stopped granting immigration clearances to Indians travelling to Iraq for one month,” foreign ministry spokesman Syed Akbaruddin told reporters.

The clearance is mostly required for Indians seeking employment in Iraq, where security forces are currently battling Sunni Muslim militants who have taken over large swathes of the country.

Those travelling for other purposes were also advised to cancel their plans, Akbaruddin said.

The spokesman further confirmed that one of a group of 40 Indian construction workers abducted on Monday in the militant-held city of Mosul had escaped.

“One person from the group managed to escape and has been in touch with our embassy in Baghdad. We can also confirm that (the) others are safe,” Akbaruddin said.

The families of several of the men met Foreign Minister Sushma Swaraj on Thursday, who promised the utmost would be done to secure their release.

“We are knocking on all doors. As diplomats we knock on front doors, now we are knocking on back doors as well as trap doors,” Akbaruddin said.

India's government estimates that around 120 of its nationals, including the 39 captured in Mosul and another group of 45 nurses holed up in the Iraqi city of Tikrit, have been caught up in the unrest.

“A total of 16 of these 120 have managed to leave the country in two batches of eight each,” the ministry spokesman said.

India was also asking the Iraqi government to alter an order that required foreign nationals to leave from their port of entry, and to ensure those crossing into neighbouring states were not denied access, Akbaruddin said.