Cargo ship taken by Somali pirates

NAIROBI (Reuters) - Somali pirates have captured a South Korean cargo vessel off Mogadishu port in the latest seizure in one of the world's most dangerous waterways, a regional maritime official said on Tuesday.

Andrew Mwangura, head of the East African Seafarers' Assistance Programme, said shipping sources in Somalia had confirmed the boat was taken on Monday or early on Tuesday.

There were 22 crew members on board.

"We have no more details yet," he said. "But the situation is getting really bad in those waters."

On Sunday, pirates hijacked a Japanese-owned chemical tanker off Somalia with 23 people on board. Four other boats -- a Comoros-registered cargo ship, two Tanzanian fishing vessels, and a ship from Taiwan -- are also being held by armed groups.

Without central government since 1991, Somalia's waters have become among the world's most perilous despite calls for international action to patrol them.

Attackers generally use speedboats to surround and board vessels, often justifying their actions as measures against illegal fishing and toxic dumping.

Mwangura said the recent upsurge in attacks may be a response to threats by the U.N. Security Council and others to take action against piracy.

"These people are sending out a message of defiance," he said. "The Security Council was talking about this problem a few weeks ago, but has taken no action."

Piracy off Somalia dropped briefly last year during a six-month period in which most of the south was ruled by a hardline Islamist movement. Incidents have risen again since the sharia courts movement was toppled in Mogadishu at New Year.