BRUSSELS, Aug 25 (AFP) - NATO remains on alert to protect the Olympics from extremists, even if no incidents have occurred and the perceived threat remains low as the Games move into their last few days, an official said Wednesday.
The North Atlantic Treaty Organization is providing round-the-clock aerial surveillance over Athens during the Games, which started on August 13 and are due to end this weekend.
"You never know what can happen but we don't see any particular clearly identified terrorist or other threat on the horizon," said a NATO official, adding there was "still a relatively low threat assessment" around the Games.
"Of course we'll continue operations right till the end. You can never let down your guard," he said, adding that the attacks on the 1972 Munich Games and in Atlanta in 1996 both came in the second half of the Games.
"We're well aware of that," he said. "So far so good," he added.
In Munich 18 people were killed following a Palestinian attack on the Israeli team, while a bomb killed one and injuring more than 100 others in Atlanta.
The Greek government appealed to NATO for help in protecting the Athens Games following extremist attacks on four suburban trains in Madrid on March.
NATO's AWACS surveillance aircraft can detect low-flying planes over long distances and cover 310,000 square kilometers (120,000 square miles) of territory -- about two and a half times the total surface area of Greece.
NATO has also sent eight warships to the region from its force permanently stationed in the Mediterranean and a unit specialized in defending against nuclear, biological and chemical attack.
The alliance also has put a force of 400 soldiers on standby in Germany, ready to intervene in Greece if the need arises during the games.
NATO, which will continue its Olympics protection operations into September, has underlined that the Greek government had full responsibility for the overall Olympic security operation.