Greece's deadliest terrorist group claimed responsibility Thursday for a spate of attacks against American targets, including an anti-tank rocket blast at a Citibank branch.

November 17, whose 21 victims since 1975 include a CIA station chief and three other Americans, said the campaign was "aimed against American imperialism-nationalism."The statement did not name any specific U.S. officials. But the wave of attacks has coincided with the high-profile activities of the new American ambassador in Athens, Nicholas Burns, who has spoken out about the need for Greece to crack down on terrorism.

"Someone might disagree with this form of struggle, might consider it terrorism, might doubt its effectiveness, but he can't deny the fact of this struggle," said a statement from the group published in the daily newspaper Elef-ther-o-typ-ia.

The group, built around a mix of ultra-leftist and nationalist id-e-ol-o-gies, is named for the day in 1973 when the then-ruling military junta crushed a student uprising in Athens. No group member has ev-er been arrested.

The statement appeared a day after the anti-tank missile attack on the Citibank branch. The other bombings, which began late last year, came at night and targeted U.S. car dealerships and McDonald's restaurants. All caused damage but no injuries.

Eleftherotypia said an anonymous telephone call disclosed the location of the November 17 communique - a rubbish bin in central Athens.

The November 17 statement, which featured its trademark star-shaped stamp, railed against the United States' "undermining of Greece's sovereign rights" through its stance on Greece's disputes with Turkey in the Aegean Sea and the war-divided island of Cyprus.

The declaration also made frequent references to the 1996 crisis over the uninhabited Greek island of Imia, which led Greece and Turkey to the brink of war because of rival territorial claims. The United States helped mediate a set-tle-ment.

November 17 is Greece's most prolific and violent terrorist group. It first emerged in 1975 with the murder of Richard Welch, the CIA station chief in Athens. Since then it has killed Americans, Greeks and Turks.