Three South Koreans were taken as hostage and released by Sinai tribesmen this year [Reuters]

At least 20 Jordanian nationals are trapped in Ras Sidr area in the governorate of south Sinai in Egypt, officials said.

"They can't move because the road is being blocked by tires set on fire by Bedouin protesters demanding the release of Sinai prisoners - this has been going on for the past few hours," an Egyptian interior ministry source told Al Jazeera.

It is unclear whether those whose movement has been blocked were tourists or migrant workers.

The incident follows a string of kidnappings in South Sinai.

The AP news agency reported earlier this month that armed tribesmen stopped a tour bus in the same area and took three South Koreans as well as their guide.

One week prior to their kidnapping, two Americans were taken not far from the St. Catherine's Monastery by tribesmen.

Officials said both incidents were linked to Ali Dikheil, an inmate they said had escaped from prison during the revolution.

Although Egyptians are also kidnapped occasionally, tribesmen in the region often abduct tourists - who are seldom harmed - in the hope that they can be swapped for imprisoned colleagues, according to the AP.