(CNN) -- NATO forces patrolling the Gulf of Aden foiled a pirate attack on a Norwegian tanker this weekend, a NATO spokesman said.

The Canadian navy's HMCS Winnipeg helped foil a pirate attack on a Norwegian tanker Sunday, NATO says.

Pirates attempted to capture the MV Front Ardennes at 6 p.m. Saturday and were apprehended seven hours later, Commander Chris Davies told CNN.

A NATO-supported Canadian navy ship, the HMCS Winnipeg, was returning from escorting a World Food Program vessel in the gulf when it saw the Norwegian ship under attack, Davies said. A British Royal Fleet Auxiliary vessel, the Wave Knight, was also in the area.

The pirates were captured at 1 a.m. Sunday after they threw weapons, ladders and scaling equipment overboard, Davies said. Several rounds of ammunition were found on the pirates' boat.

The pirates were detained, but allowed to go free after questioning.

There is currently no formal procedure for NATO personnel to follow once they have apprehended pirates, Davies noted. Their weapons are confiscated and they are then typically given provisions and released.

The Sunday incident is the latest in a string of hijackings off the Horn of Africa, which have received more attention since pirates attacked a U.S.-flagged cargo ship on April 8 and took its captain hostage. See a map of pirate attacks »

On Saturday, Dutch naval forces captured seven pirates and freed 20 captive fishermen after tracking the pirates to their "mother ship" in the western Gulf of Aden. The rescue came as pirates were capturing another vessel -- a Belgian ship -- off the coast of the Seychelles islands.

On Wednesday, the French navy captured 11 suspected pirates off the coast of Kenya, the French Ministry of Defense announced. The French launched a helicopter from the frigate Nivose to head off an attack on a ship Tuesday night, then seized the suspected pirates Wednesday morning, the statement said.

On Tuesday, the Liberty Sun, a U.S.-flagged cargo ship bound for Mombasa, Kenya, was attacked by Somali pirates, according to a NATO source with direct knowledge of the matter. The pirates never made it onto the ship.

Also Tuesday, pirates in the Gulf of Aden hijacked the MV Irene EM, a 35,000-ton Greek-owned bulk carrier, according to a NATO spokesman and the European Union's Maritime Security Center.

Later Tuesday, pirates on four skiffs seized the 5,000-ton MV Sea Horse, a Lebanese-owned and Togo-flagged vessel, Davies said.

On Monday, pirates hijacked two Egyptian fishing boats carrying a total of between 18 and 24 people, the Egyptian Information Ministry told CNN.

The hijacking of the U.S.-flagged ship, the Maersk Alabama, began when pirates attacked the vessel about 350 miles off Somalia's coast on April 8. The crew quickly regained control of the ship, but the captain, Richard Phillips, was taken hostage and held for five days in a covered lifeboat. On April 12, U.S. Navy snipers killed three pirates holding Phillips. A fourth pirate was taken into custody. Pirates in Somalia said later that Tuesday's attack on the Liberty Sun was a response to the killing of Phillips' captors.

CNN's Carol Jordan in London, England, contributed to this report.

All About Pirates • NATO • Somalia