DUBAI (Reuters) — Three of the Middle East's top oil exporting nations, Saudi Arabia, Iran and Kuwait, have no immediate plans to alter their crude oil shipping operations despite an increased threat from pirates off East Africa.

Somali pirates over the weekend hijacked a Saudi supertanker with a cargo of two million barrels of oil and the US navy said it was now anchored off Somalia.

The US Navy said yesterday pirates had transported the Sirius Star – seized 450 nautical miles southeast off Kenya in the boldest strike to date by Somali pirates – to Haradheere port half-way up the Horn of Africa nation's long coastline.

"At this time, Vela is awaiting further contact from the pirates in control of the vessel," said Dubai-based owner Vela International, shipping arm of state oil giant Saudi Aramco.

A Hong Kong cargo ship loaded with wheat bound for Iran was hijacked by pirates in the Gulf of Aden on Monday.

The Delight, with 25 crew members on board, was captured off the Yemen coast, the official Xinhua agency said, citing China's Maritime Search and Rescue Centre.

And the Tianyu No. 8 was seized November 15 while fishing off the coast of Kenya, China's official Xinhua News Agency said, citing an unidentified official at the Transport Ministry.

Using larger "mother ships" to increase their reach, the heavily armed pirates usually pull up on either side of a target in speedboats and board, firing guns or even rocket-propelled grenades just over the bridge if the captain tries to escape.

Somalia, which has had no functioning government since 1991, has become a world piracy hot spot, with at least 83 attacks this year on ships off its coast and 33 ships successfully hijacked.

The stepped-up attacks have prompted several countries to send navy ships to patrol the waters off Somalia.

Twelve vessels — including a Ukrainian freighter loaded with tanks and weapons that was seized September 25 — remain in the hands of pirates along with more than 200 crew.

Many of the attacks have come in the Gulf of Aden, one of the world's busiest waterways with about 20,000 ships sailing through each year. However, increasingly bold Somali pirates have also been ranging further south off the coasts of countries such as Kenya.

Last Thursday, pirates armed with grenade launchers and automatic weapons attacked a Russian-operated freighter off the coast of Somalia, but the vessel outran its attackers.

A day earlier, Russia's navy said Russian and British ships had repelled a pirate attack on a Danish freighter in the Gulf of Aden, sending up helicopters.

A NATO flotilla of seven vessels is also patrolling the Gulf of Aden to help the US Fifth Fleet in anti-piracy patrols and to escort cargo vessels.

The Fifth Fleet said it has repelled about two dozen pirate attacks since August 22.

China's navy is mainly intended for coastal defence and has little experience operating away from its home ports.

Andrew Mwangura, coordinator of the East African Seafarers' Association, said he thought a hijacked Nigerian tug was a "mother-ship" for the Sirius Star seizure. The fully-loaded supertanker was probably low in the water and therefore easy to board by ladder or rope, he said.

Normally, well-armed and sophisticated Somali pirates use speedboats and satellite phones to coordinate attacks, with the mother-ship as a base for their operations. The seizure of the 1,080 foot long Star, follows another high-profile strike earlier this year by the pirates when they captured a Ukrainian ship carrying 33 tanks and other military equipment.

They are still holding that vessel and about a dozen others, with more than 200 crew members hostage. Given that the pirates are well-armed with grenades, machineguns and rocket-launchers, foreign forces in the area are steering clear of direct attacks.

Ship owners are negotiating ransoms in most cases. The capture of the Star is one of the most spectacular strikes in maritime history.

"It looks like a deliberate (middle finger) from some very bright Somalis. Anyone who describes them as a bunch of camel herders needs to think again," one Somalia analyst said.

Top oil exporter Saudi Aramco's export shipping operations were unchanged despite the seizure, a spokesman for the state owned company's shipping arm, Dubai-based Vela International, said.

"There is no suspension of shipping operations," the spokesman told Reuters. "Operations globally are continuing as per normal. This is an unfortunate incident, and this region is very sensitive."

Vela owns and operates a fleet of 19 supertankers which trade mainly between the Middle East, Europe and the US Gulf Coast.

The company transports about three million barrels per day of Saudi Arabia's seven million bpd of exports. Just over half of Saudi Arabia's oil exports head east to Asia, while most of the rest goes west to Europe and the United States.

Europe-bound barrels travel past the Bab el Mandab strait, the entry from the Gulf of Aden to the Red Sea. This chokepoint has long been at risk of pirate attacks launched from Somalia.

US-bound barrels travel what was previously considered a safer route around the southern tip of Africa. But the Sirius Star was on that route and was seized far from the Gulf of Aden.

Iran, the second-largest exporter in the Organization of the Petroleum Exporting Countries (OPEC), has also kept its shipping operations unchanged, an official from the state-run National Iranian Tanker Company (NITC) said. Iran exports about a quarter of its oil to Europe, and the rest to Asia. Sanctions prevent Tehran from exporting crude to top oil consumer the United States.

"We haven't made any decision to avoid the region where these pirates have been attacking," the official said. "We have been very careful when travelling in this region, but now we have to be even more careful."

Kuwait's state oil shipping firm, Kuwait Oil Tanker Company (KOTC), said that it had not altered its activities.

"Everything is running normally, we have not made any changes, this is not affecting us," a company spokesman said.

Kuwait exports about 2.15 million barrels per day and ranks as the fourth-largest OPEC exporter. Crude oil transportation via supertankers from the Middle East have little option but to keep rounding the Cape of Good Hope, shipping sources said.

"The VLCC (Very Large Crude Carrier) being fully laden would have to go around the Cape of Good Hope anyway if it's going to the West," said an Asian-based supertanker broker.

"So it does not really matter in that instance what they do, except they could take a route further east in the Indian Ocean, they will have to travel further away from the coast."

The longer route would drive up the cost of shipping crude, as would higher insurance premiums for plying routes in the region seen at risk from piracy, Samuel Ciscuk, Middle East analyst at Global Insight, said in a report.

"The successful targeting of the ship therefore heralds new tangible threats to one of the world economy's lifelines, bringing virtually all crude shipping from the Gulf to the West in range of possible attacks," Ciscuk said.