Pirate attacks have jumped 14 percent this year, with Somalia and Nigeria the worst hotspots, a watchdog said Tuesday, warning a three-year drop in crime on the high seas may be at an end.

The International Maritime Bureau (IMB) recorded 198 incidents in the first nine months of 2007, compared to 174 in the same period last year. Somalia alone recorded 26 attacks compared to eight last year.

"The level of violence in the high-risk areas remains unacceptable," IMB director Pottengal Mukundan said in a statement.

"Pirates in Somalia are operating with impunity, seizing vessels hundreds of miles off the coast and holding the vessel and crew to ransom, making no attempt to hide their activity."

The IMB said there had now been two successive quarters showing an increase in piracy attacks recorded by its Malaysia-based Piracy Reporting Centre.

"If this current trend continues, it would appear that the decline in piracy attacks since 2004 has bottomed out," it said.

So far this year, 15 vessels have been hijacked, three crew members were killed, 172 were taken hostage, 63 were kidnapped and 21 were assaulted.

The IMB said the past nine months "represent one of the highest numbers of attacks reported off this troubled coast of East Africa" and that Nigeria had also seen a "drastic increase" with 26 attacks compared to nine last year.

"Despite having a strong naval and police force Nigeria has not been able to control the increase in attacks directed towards the vessels in the oil sector. Criminal groups claim to have political motives for theft and abduction of crew members," it said.

Meanwhile, the Malacca Straits which runs between Indonesia and Malaysia has been "relatively quiet," it said, with most incidents involving armed theft taking place in ports.

"This improvement is largely attributed to the co-operation between states bordering these waters and the efforts of the Indonesian authorities," it said.