Four senior officials of Posco-India, including three South Korean nationals, were on Saturday taken hostage by an anti-project group at the company's proposed captive port site near Paradip in Orissa's Jagatsinghpur district, official sources said.

The senior executives held in the captivity of the anti-project group were identified as K S Choi, General Manager (Construction), S H Nam, T J Aan (both engineers) and D Ojha, an Oriya official, company sources said.

"The foreign nationals were in captivity since more than three hours," Jagatsinghpur Collector P K Meherda told PTI over telephone.

He said efforts were on to ensure safe release of those detained, including the South Korean nationals.

Meanwhile, Posco Pratirodh Sangram Samiti which has been opposing the South Korean company's steel project, claimed that its activists rounded up the officials when they were undertaking survey near the proposed port site.

"The three Koreans and one Oriya officer are in our captivity. They are safe," PPSS president Abhay Sahu told PTI, adding that the officials were held hostage as they deliberately entered the "restricted" area.

This is the third incident in the last three days when PPSS activists took at least 13 Posco officials into captivity when they tried to enter the proposed steel plant area, sources said.

Three officials, including Posco-India's Kujang office General Manager Ardhendu Mohapatra who were taken hostage on Thursday had, however, escaped from the clutches of their captors on Friday night, they said.

"They escaped while our activists were sleeping," said PPSS general secretary Sisir Mohapatra.

Sahu said the people opposing the Posco project had raised bamboo gates and barricades near the villages to prevent any government and company officials from entering the area ever since the company inked MOU with the state government.

The PPSS maintained that they had pledged not to allow the South Korean company's proposed Rs 52,000 crore green field project near Paradip. "We are opposed to the project because it will displace people," Sahu said.

According to Posco-India spokesman Sashanka Patnaik, the four executives had gone to the proposed port site through a different route.

"We were not expecting that the PPSS activists would capture them," he said appealing to the anti-project activists to release the Koreans as they were foreign nationals.