NATO Sub Intrudes in Israeli Waters (?)

Lots of sub news on the 'net tonight. Here's an interesting article from the Jerusalem Post about the Israeli Navy detecting and "chasing off" a foreign, probably NATO, submarine from its territorial waters off their northern coastal waters. I'm much more dubious of this claim than I am of the Japanese claim discussed below (which turned out to be correct). If it was a submarine, it was almost certainly a NATO boat, since the Arab countries with submarines (Egypt, Algeria, Libya -- the best source for Third World naval Order of Battle is probably found here) wouldn't dare go near Israel, even it their boats could submerge, especially while Israel was on alert due to Arafat's death. Who, then, might it have been? Germany wouldn't dare go near Israel, and the other northern European diesel boat operators rarely will go into the Med. Turkey, Italy, and Greece probably wouldn't risk their diesel boats on a mission like this; so maybe it was one of the countries operating nuclear boats. That would be France, Great Britain, and the US. France would be unlikely to send a boat in immediately following Arafat's death in Paris. Would the Brits or Americans do such a thing? I have no idea (see my first post for more on why I have no idea). Probably they were tracking a horny whale...

Update: Here's an interesting tidbit that says the intruding sub may not have belonged to a "friendly, Western country". An unfriendly Western country, perhaps?