MOGADISHU: Somali pirates said on Tuesday they had seized a yacht in the Indian Ocean with a British couple aboard and were taking the vessel to the Horn of Africa nation.

"The British couple are in our hands now. We captured them as they were touring in the Indian Ocean," a pirate called Hassan told Reuters. He said the two captives were healthy and ransom demands would follow.

"We are currently in touch with the family in the UK and the Seychelles coastguard who continues to monitor the situation and has conducted a search of the area," Matthew Forbes, British High Commissioner to the Seychelles, told Reuters.

Pirates have plagued busy shipping lanes off the coast of Somalia for several years. Foreign navies have warships in the area to try and prevent hijacks, but the sea gangs have started to hunt for ships far into the Indian Ocean.

The pirates typically use "mother ships" to sail hundreds of miles to sea and then launch attacks in small skiffs, armed with assault rifles and rocket-propelled grenade launchers.

The gangs -- some made up of former fisherman angered by the presence of foreign fishing vessels in their waters -- have made tens of millions of dollars in ransoms.

Seychelles Warning

In their most audacious attack, pirates hijacked a supertanker with $100 million worth of oil on board in November last year. It was released after a $3 million ransom was paid.

While there was a relative lull in hijackings in Indian Ocean waters during the middle of 2009 because of monsoon rains, the number of attacks has increased in the past month.

Pirates seized a Spanish tuna fishing vessel early in October and a Chinese bulk carrier later in the month. A number of other unsuccessful attacks have been reported.

Maritime security groups also warned in May of a surge in the number of pirate "mother ships" operating in the Seychelles archipelago's expansive territorial waters.

The US military said in August it would be deploying unmanned reconnaissance aircraft in the skies above the Seychelles to bolster anti-piracy efforts.

The kidnapped British couple were sailing to the east African country of Tanzania when they were seized.

A final message on the couple's blog posted at dawn on Friday morning read: "Please ring Sarah". There has been no communication with the 38-foot yacht, Lynn Rival, since then.

A diplomatic source said the Seychelles coastguard had launched a search operation on Friday but there had been no confirmed sighting of the vessel.

Maritime sources were unable to confirm the location of the vessel at the time the emergency beacon was activated.

A sailors' forum on the Internet quoted the US National Intelligence Agency as saying the distress signal was picked up at 0133 GMT on Friday and that the vessel was 60 nautical miles (111 km) west of Victoria, the Seychelles' capital.