The Nigerian group that took credit for freeing two kidnapped American sailors from a supply vessel last month claims the caper netted a $2 million ransom.

In an email to the shipping blog G-Captain, the Movement for the Emancipation of the Niger Delta (MEND) said it arranged the release of the two unidentified crew members kidnapped from the Edison Chouest-owned supply vessel C-Retriever. Officials at Louisiana-based Edison-Chouest did not immediately return calls seeking confirmation of the ransom amount.

The sailors were grabbed by pirates Oct. 23 and taken ashore, where they were held for nearly three weeks. Although the State Department confirmed last week they were released, no names or details were revealed other than that a ransom was paid, according to Drew Bailey, a State Department spokesman.

The two sailors, identified as the ship’s captain and chief engineer, were kidnapped from the 200-foot-long ship C-Retriever as it sailed near Brass, Nigeria, in the Gulf of Guinea. MEND rebels later told The Associated Press that they had been contacted by the kidnappers and said a rescue operation was under way.

Despite a recent decrease in attacks worldwide, pirates in the Gulf of Guinea have accounted for at least 30 piracy incidents this year, including two hijackings, according to the International Chamber of Commerce’s Maritime Bureau. By comparison, 11 reported incidents, including two hijackings, have occurred off Somalia. Globally, 206 incidents and 11 hijackings have been tallied this year, according to statistics provided by the organization earlier this month.

G-Captain reported that it appears to be the first time that specific details of a ransom payment have been made public as the result of a kidnapping incident off Nigeria. But the blog was careful to say it could not vouch for the credibility of the group that sent the email. The rebel group claimed in the email the hostage situation “ended on a happy note” and they claim to have in some way influenced the positive outcome. Furthermore, they note that the ransom payment was allegedly paid in large part from the Nigerian Maritime and Safety Administration Agency (NIMASA).