NAIROBI, Kenya (AP) — Somali pirates have collected more than $150 million in ransoms over the past year, Kenya’s foreign affairs minister said today, calling on ship owners not to pay when their vessels are hijacked.

In the past two weeks Somalia’s increasingly brazen pirates have seized eight vessels including a huge Saudi supertanker loaded with $100 million worth of crude oil. Several hundred crew are now in the hands of Somali pirates.

“We are advised that in the last 12 months, ransom to the excess of $150 million has been paid to these criminals and that is why they are becoming more and more audacious in their activities,” Kenyan Foreign Minister Moses Wetangula said.

Saudi Arabia’s foreign minister said today that the Saudi government was not and would not negotiate with pirates, but what the ship’s owners did was up to them.

Meanwhile, the world’s largest oil tanker company warned that it may divert cargo shipments, which would boost costs up to 40 percent.

Frontline Ltd., which ferries five to 10 tankers of crude a month through the treacherous Gulf of Aden, said it was negotiating a change of shipping routes with some of its customers, including oil giants Exxon Mobil, Shell, BP and Chevron.

Martin Jensen, Frontline’s acting chief executive, said that sending tankers around South Africa instead would extend the trip by 40 percent.

Bermuda-based Frontline plans to make a decision whether to change shipping routes within a week, Jensen said.

“It’s not only our costs, but also those of the people who have a $100 million cargo on board,” Jensen said. “We’re not going to make a unilateral decision so we’ve been debating this with our customers.”

A.P Moller-Maersk, the world’s largest container-shipping company, on Thursday ordered some of its slower vessels to avoid the Gulf of Aden and head the long way around Africa.

The Copenhagen-based company said it was telling ships “without adequate speed,” mainly tankers, to sail the long route around Africa unless they can join convoys with naval escorts in the gulf, group executive Soeren Skou said.

The company didn’t say how many ships would be affected by the decision, but said it usually has eight tanker transits in the area per month. The company says it handles 16 percent of the world’s container-shipping traffic.

And Norwegian shipping group Odfjell SE on Wednesday ordered its more than 90 tankers to avoid the Gulf of Aden because of the risk of attack by pirates.

A Russian frigate, meanwhile, was escorting nine ships in the pirate-infested waters off the coast of Somalia, Russian news agencies reported. They included a Russian vessel and eight other commercial ships flying flags of Liberia, the Marshall Islands and the Cayman Islands.

The Somali pirates have the support of their communities and rogue members of the government. Often dressed in military fatigues, pirates travel in open skiffs with outboard engines, working with larger ships that tow them far out to sea. They use satellite navigational and communications equipment and an intimate knowledge of local waters, clambering aboard commercial vessels with ladders and grappling hooks.

They are typically armed with automatic weapons, anti-tank rocket launchers and grenades — weaponry that is readily available throughout Somalia.

On Thursday, the African Union urged the United Nations to quickly send peacekeepers to Somalia but that appeared unlikely anytime soon.

A U.N. peacekeeping operation in the early 1990s saw the downing of two U.S. Army helicopters and killing of 18 American soldiers. The U.S. withdrew and U.N. peacekeepers were gone by 1995.

In New York, the U.N. Security Council voted unanimously to authorize its sanctions committee to recommend people and entities that would be subject to an asset freeze and travel ban for engaging in or supporting acts that threaten peace in Somalia, for violating a U.N. arms embargo, and for obstructing delivery of humanitarian aid.

— Associated Press Writer Alex Kennedy in Singapore contributed to this report.