African waters are among the most perilous in the world, says a new piracy report by the International Maritime Bureau.

Piracy in waters off Nigeria, Somalia and Tanzania is on the rise, according to an analysis of shipping records for the first nine months of 2007. The once notorious Malacca Straits in South-east Asia continues to show a decline in attacks.

Overall, piracy incidents have risen 14% in the first nine months of 2007, compared with the same period in 2006. The number of attacks was 198, against 174 previously.

A total of 15 vessels were hijacked, with 172 crew members taken hostage, 63 kidnapped, and 21 assaulted.

"If this trend continues, the decline in piracy attacks that began in 2004 will have bottomed out," the report said. "Crew assaults, kidnapping and ransom rose dramatically from 2006."