Six Ukrainian sailors have been released from pirate captivity in Nigeria: five have already returned to their homeland, and the sixth is completing treatment in the Netherlands, Ukrainian Foreign Minister Pavlo Klimkin has said.

"Thanks to joint efforts with the Dutch and Nigerian friends, we have managed to free six of our compatriots from the pirate captivity ... Five sailors - citizens of Ukraine have arrived to their homeland this morning. All are alive and well. Another of our sailors remains in the Netherlands for treatment, but in the near future he will return home," Klimkin wrote on his Facebook page on Thursday.

The minister specified that the sailors had been held hostage for almost a month in the Niger delta.

"I am deeply grateful to our Dutch and Nigerian partners for their sincere care and painstaking round-the-clock work, thanks to which they managed to save human lives," Klimkin wrote.

The Ukrainian minister assessed such joint actions as "an example of international mutual assistance in the fight against piracy of the 21st century."