The U.N. Security Council has extended for another year its authorization for countries to enter Somalia's territorial waters, with advance notice, and use "all necessary means" to stop acts of piracy and armed robbery at sea.

Virtually all the world's nations have powers under the 15-nation council's unanimous resolution Tuesday to repress the increasingly brazen pirates off Somalia. Before acting, however, nations must first have the approval of Somalia's weak U.N.-backed government, which also must give advance notice to U.N. Secretary-General Ban Ki-moon.

Diplomats said such sweeping authorizations are needed to stop the piracy off Somalia that threatens humanitarian efforts and regional security, and seems to be growing ever more audacious and technologically sophisticated each week.

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The resolution extends until one year from now a measure first approved in June that granted authorization to foreign ships to enter Somali waters when fighting piracy and armed robbery along the country's 1,880-mile coastline, the continent's longest.

A maritime official said Tuesday that pirates chased and shot at a U.S. cruise ship with more than 1,000 people on board but failed to hijack the vessel as it sailed along a corridor patrolled by international warships.

The London-based International Maritime Bureau, which fights maritime crime, could not say how many cruise liners use the waters. International warships patrol the area and have created a security corridor in the region under a U.S.-led initiative, but attacks on shipping have not abated.

With the deteriorating situation in Somalia — both on land and at sea — threatening some of the world's most important shipping routes, Russian Ambassador Vitaly Churkin called the pirates' goals "ever-expanding."

In September, pirates seized a Ukrainian freighter loaded with 33 battle tanks and on Nov. 15 they seized a Saudi oil tanker carrying $100 million worth of crude oil.

About 100 attacks on ships have been reported off the Somali coast this year and 40 vessels hijacked, with 14 still remaining in the hands of pirates along with more than 250 crew members, according to maritime officials.

The latest council resolution, which had been pushed by France and the United States, was in part a response to requests for help from both the Somali government and the U.N. chief.

Somalia's transitional president Abdullahi Yusuf told council members in Djibouti earlier this year that "the issue of piracy is beyond our present means and capabilities."

Somalia, a nation of about 8 million people, lacks a navy. It has not had a functioning government since warlords overthrew a dictator in 1991 and then turned on each other. The current government, formed in 2004 with the help of the U.N. and backed by Ethiopia, has failed to protect citizens while it battles a growing Islamist insurgency.

Last month, the council voted to impose sanctions on pirates, arms smugglers, and perpetrators of instability in Somalia in a fresh attempt to help end the years of lawlessness in the Horn of Africa nation.

A council panel was authorized to recommend people and entities whose financial assets would be frozen and who would face a travel ban. It also reaffirms an arms embargo.

Somali pirates preying on international shipping are also damaging their homeland's battered economy, worsening the instability that opened the door to piracy and inroads by Islamic extremists, according to the U.N., which also reports that inflation is "unbridled," especially in south-central Somalia where fuel costs and food prices are soaring.

Since January, the number of Somalis in need of humanitarian aid has increased from 1.8 million to more than 3 million.