* International forces rescue hijacked Chinese vessel
* Three other ships seized
* United Nations gives green light to pursue pirates on land
By David Clarke
NAIROBI, Dec 17 A multilateral force rescued a Chinese ship from Somali pirates on Wednesday, in a sign foreign navies patrolling the shipping lane linking Europe to Asia are adopting tougher new tactics.
The Chinese boat Zhenhua 4 was one of four vessels seized by pirates on Tuesday, the same day the United Nations Security Council took a strong stand against the attacks and authorised countries to pursue the gunmen on land.
A Kenyan maritime group said the crew locked themselves in their cabins and radioed for help. A warship and two helicopters came and fired on the pirates, but did not kill them, it said.
Chinese state media said a "multilateral" force with helicopters hovered over the ship and successfully fought off the pirates.
Rampant piracy off the coast of Somalia this year has earned gunmen millions of dollars in ransom, hiked shipping insurance costs and caused international alarm.
The seizures have prompted some of the world's biggest shipping firms to switch routes from the Suez Canal and send cargo vessels around southern Africa instead -- which could push up the cost of commodities and manufactured goods.
Foreign navies have rushed to patrol shipping lanes off the Horn of Africa nation, but have had little impact so far on the pirates who mostly operate out of northern Somalia.
According to the Andrew Mwangura of the East African Seafarers Assistance programme, there have been 124 incidents of piracy off Somali this year and some 60 successful hijacks.
Nearly 400 people and 19 ships are being held along the coast, including a Saudi supertanker with 2 million barrels of oil and a Ukrainian cargo ship with 33 tanks.
VERY ROBUST APPROACH
Last week the European Union launched an anti-piracy operation with warships and aircraft from Britain, France, Greece and Spain, and pledged to take a "very robust" approach.
China is reported to be seriously considering sending naval ships to the region to escort vessels and Kenya said this week it would sink any pirates carrying out attacks in its waters.
Mwangura said on Wednesday the Chinese vessel, with 30 Chinese crew, and a yacht with two on board had been seized off Yemen a day earlier. A tugboat and a 100-metre (330-ft) cargo ship belonging to an Istanbul-based shipping company were also taken in the Gulf of Aden on Tuesday.
Analysts say the problem must be tackled on land as well, but the weak Somalian government says it does not have the resources to tackle the buccaneers.
The country has been in virtual anarchy since the collapse of a dictatorship in 1991. Islamist insurgents control most of the south and feuding clan militias hold sway elsewhere.
The fractured Western-backed administration controls only the capital Mogadishu and the seat of parliament Baidoa, while pirates are mostly based in the northern Puntland region.
The resolution passed by the 15-nation Security Council on Tuesday said states "may undertake all necessary measures in Somalia, including in its airspace" to stop the pirates.
The Security Council called on countries to "take part actively" in the fight against piracy and Washington said the United Nations should deploy a peacekeeping force.
Authorities in the semi-autonomous region of Puntland welcomed the decision to take the battle onto land.
"We, Puntland authority, have agreed to support this resolution. And we want our security forces to work with the U.N. forces because we are the main victims of piracy," Abdulqadir Muse Yusuf, Puntland's assistant minister for fisheries, told Reuters.
Iran also called for tougher action on Tuesday, saying five of its oil tankers had been attacked this year and the cost of crude could rise if strategic sealanes went unprotected.
Somalia's neighbour Kenya also began extensive air and sea patrols this week. "We are daring them to try any attacks on Kenyan waters and we will sink them," Chief of General Staff Jeremiah Kianga said on Monday. (Additional reporting by Wangui Kanina in Nairobi, Celestyne Achieng in Mombasa, Abdiqani Hassan in Bosasso and Ian Ransom and Sally Huang in Beijing; editing by Andrew Roche)