Updated

Four Thais held in an apparent ransom kidnapping in Nigeria have been freed unharmed, a spokesman for the kingdom's foreign ministry in Bangkok said Saturday.

A gang of armed kidnappers seized the four Thais and two Nigerians on a waterway while they were on their way to work at a state-owned fish farm in the African nation's southern Rivers State, Nigerian officials said last week.

"All of them are released," ministry spokesman Manasvi Srisodapol said of the Thai nationals.

"The Thai Foreign Minister has talked with one of them. They are fine and will continue to work in Nigeria," he added, without confirming whether a ransom was paid or the exact time of their release.

It was unclear what happened to the Nigerian hostages.

Kidnaps for ransom are common in the remote and gang-ridden area.

Most kidnap victims in southern Nigeria are released unharmed after the payment of a ransom, unlike in the country's north, where Islamist extremists have killed a number of their hostages.

One of Thai hostages spoke to Thai television on Saturday and said he believed the kidnap was linked to rivalry between competing fish farms.

"They took us as hostages and used us as a bargaining chip," Somchoke Panpinij told Thailand's Channel 7.

"We will not return to Thailand yet... I came here to help them to develop their country."