BAGHDAD (Reuters) - Iraq’s security forces said on Monday they had made arrests related to the kidnapping and holding hostage of six of their members by Islamic State militants.

The militants had kidnapped six men and on Saturday threatened to kill them in three days unless the government released Sunni Muslim female prisoners.

In a video released by the group, the six men identify themselves as members of the police or the Popular Mobilisation Forces, an umbrella grouping of mostly Shi’ite Iran-backed militias that fought with government forces against Islamic State and nominally report to Prime Minister Haider al-Abadi.

They were kidnapped on the highway connecting Baghdad to Iraq’s north, a road that has seen an uptick in attacks by the Islamic State in recent weeks.

Abadi met security and intelligence leaders on Sunday and ordered the formation of a special force to secure roads and protect travelers, the security forces said in a statement.

“This force was able to arrest elements from the terrorism and crime gangs that are related to the recent kidnapping incident on the road to Kirkuk province recently,” it said.

Abadi declared final victory over the hardline Sunni militants in December but the group still operates from pockets along the border with Syria and has continued to carry out ambushes, assassinations and bombings across Iraq.