The sister of a woman jailed in Egypt for alleged ties to the outlawed Muslim Brotherhood urged the Islamic State group on Friday not to kill a Croatian hostage they are holding.

 

The extremist group had earlier said it would kill the hostage, 30-year-old Tomislav Salopek, in the coming hours if the Egyptian government did not release jailed "Muslim women" — a reference to female Islamists detained in Egypt in the government's broad crackdown on Brotherhood supporters.

 

Salopek, a surveyor in the oil and gas industry working with France's CGG Ardiseis, was abducted last month.

 

Doaa el-Taweel, sister of jailed photographer and activist Esraa el-Taweel, said that her sister is innocent and that "her release should not come at the expense of another innocent person."

 

Extremists of the Islamic State released a video on Wednesday threatening to kill Salopek, a father of two, in 48 hours if authorities failed to respond to their demands.

 

Esraa el-Taweel disappeared in June for weeks before the Interior Ministry announced that they arrested her on charges of belonging to the Brotherhood, which had been declared a terrorist organization, and for spreading false information to tarnish the country's image. She is now awaiting trial.

 

Croatian President Kolinda Grabar-Kitarovic said Friday she would talk to her Egyptian counterpart, Abdel-Fattah El-Sissi, about the Salopek kidnapping, and that Croatian authorities were doing all in their power to resolve it.

 

She said she could not go into specifics because of Salopek's security and that of "all Croatian citizens who work in places where there is a danger of kidnapping."

 

A day earlier, Croatian state television said that Foreign Minister Vesna Pusic flew to Cairo together with Salopek's wife, Natasha.

 

An Egyptian security official said that forces were searching for the Croatian hostage across the country, in particular in the provinces of Matrouh, in the west bordering Libya; Beheira, in the Nile Delta; Wadi Gedid, in the southwest and also bordering Libya; and Giza, next to Cairo.

 

The official said Salopek's driver, who the kidnappers left behind, said that the gunmen who seized the oil and gas industry surveyor off a western Cairo highway had Bedouin accents.

 

That suggests they could have come from a variety of isolated places in Egypt, including the eastern Sinai Peninsula, where Egypt's Islamic State affiliate is based, or the vast Western desert that's the gateway to volatile and lawless Libya, home to its own Islamic State branch.

 

The Egyptian official spoke on condition of anonymity because he was not authorized to speak to journalists.

 

Another Egyptian woman, the mother of two jailed female Islamists arrested at protests who are appealing life sentences, Hind and Rasha Mounir, made a similar call to the IS extremists on Friday.

 

"My girls should be released but not with the blood of innocent people," the mother of two jailed Islamists, Fatma Ahmed said.

 

Egypt has seen an increase in violence since the 2013 ouster of Islamist President Mohamed Morsi, with attacks by suspected Islamic extremists in both the Sinai Peninsula and the mainland, focusing primarily on security forces.

 

Foreign interests also have been targeted increasingly, including the Italian Consulate, which was hit with a car bomb last month.

 

But this is the first time the local Islamic State affiliate released a video showing a kidnapped foreigner in Egypt, a major escalation as the country tries to rebuild its crucial tourism industry after years of unrest following the 2011 revolt against autocrat Hosni Mubarak.