CAIRO, Aug 5 (Aswat Masriya) - A Croatian citizen kidnapped by Egyptian militants appeared in a video released on Wednesday, saying that he will be killed in 48 hours if Muslim women "arrested in Egyptian prisons" are not released.

The 30-year-old Croatian national Tomislav Salopek said "the soldiers of Islamic State" in Sinai caught him on July 22, in a video attributing itself to the media office of Ansar Bayt al-Maqdis militant group in North Sinai.  

He appears in the video in a jumpsuit and is sitting on his knees, with a man dressed in military fatigues and a mask standing behind him, resembling the execution videos released by Islamic State fighters in Iraq and Libya over the past year. 

"They want to substitute me with the Muslim women arrested in Egyptian prisons," he said.  

This matter has to be achieved "before 48 hours," Salopek said. 

"If not, the soldiers of [Sinai Province] will kill me," he added at the end of the video. 

Aswat Masriya could not independently verify the authenticity of the video.

The North Sinai-based Ansar changed its name to Sinai Province after pledging allegiance to Islamic State fighters last November.

The group has increasingly claimed responsibility for attacks in the peninsula, and has claimed at least four attacks in July alone.

The Croatian Foreign Ministry said two days after Salopek's abduction that "[the armed men] forced him to get out of the car and drove away with him in an unknown direction."

It said it was doing everything in its power to find information about the kidnapped national.

Salopek works for a French company in Egypt.

He is married and has two daughters, he said in the video.