On the same day Somali gunmen seized two more ships, the UN Security Council voted unanimously on Tuesday to authorise nations to conduct land and air attacks on pirate bases on the coast of the Horn of Africa country.
Secretary of State Condoleezza Rice was on hand to push through the resolution, one of President George W Bush's last major foreign policy initiatives.
Rice said the resolution will have a significant impact, especially since "pirates are adapting to the naval presence in the Gulf of Aden by traveling further" into sea lanes not guarded by warships sent by the US and other countries.
The council authorised nations to use "all necessary measures that are appropriate in Somalia" to stop anyone using Somali territory to plan or carry out piracy in the nearby waters. The gulf is traversed each year by thousands of cargo ships sailing between Asia and the Suez Canal.
The resolution allows action in Somali airspace, even though the US appeased Indonesia, a council member, by removing direct mention of it, US officials said.
Somalia Foreign Minister Ali Ahmed Jama, whose government asked for the help, said he was "heartened" by the council action. "These acts of piracy are categorically unacceptable and should be put to an end," he said.
The resolution sets up the possibility of increased American military action in Somalia, a chaotic country where a US peacekeeping mission in 1992-93 ended with a humiliating withdrawal of troops after a deadly clash in Mogadishu, as portrayed in the movie "Black Hawk Down."
The commander of the US Navy's 5th Fleet expressed doubt last week about the wisdom of staging ground attacks on Somali pirates. Vice Adm. Bill Gortney told reporters it is difficult to identify pirates and said the potential for killing innocent civilians "cannot be overestimated."
Spurred by widespread poverty in their homeland, which hasn't had a functioning government for nearly two decades, Somali pirates are evading an international naval flotilla to intercept huge tankers, freighters and other ships to hold for ransom. A tugboat operated by the French oil company Total and a Turkish cargo ship became the latest victims Tuesday.
Pirates have hijacked more than 40 vessels off Somalia's 1,880 mile (3,025 kilometer) coastline this year.
Before the latest seizures, maritime officials said 14 vessels remained in pirate hands _ including a Saudi tanker carrying $100 million worth of crude oil and a Ukrainian ship loaded with tanks and other heavy weapons. Also held are more than 250 crew members. Rice said the resolution will allow the tougher action needed to quell the piracy, which she blamed on Somalia's turmoil. "Once peace and normalcy have returned to Somalia, we believe that economic development can return to Somalia," she said. "This current response is a good start."
Under the resolution, nations must first get a request for an attack from Somalia's weak UN-backed government, which itself would be required to notify UN Secretary-General Ban Ki-moon before any attack.
"Piracy is a symptom of the state of anarchy which has persisted in that country for over 17 years," Ban told the council. "This lawlessness constitutes a serious threat to regional stability and to international peace and security."
In Washington, Pentagon spokesman Bryan Whitman declined to discuss any possible military operations, but acknowledged there are "practical challenges" to combating pirates.
He said the US would continue to work with allies in the region and encourage shipping companies to take prudent measures to protect their vessels.
The United Nations also has been urging shipping and insurance companies not to pay ransom for captured ships, saying that encourages more piracy.
He Yafei, China's vice minister for foreign affairs, told the Security Council that China is considering sending warships to the Gulf of Aden, where they would join ships from the US, Russia, Denmark, Italy and other countries.
Kenya's military chief, Gen. Jeremiah Kianga, said on Tuesday his country will increase patrols along its own coast because the Somali piracy has made business at Kenya's main port more expensive. The Kenyan air force and navy will not enter Somali air space or waters, he said.