The U.S. Embassy today dismissed charges by the Greek government that American military aircraft violated Greece's "flight information region" yesterday. Greece said U.S. and Turkish warplanes on a North Atlantic Treaty Organization exercise over the Aegean Sea entered the area without submitting flight plans.

The Greek government, which also protested to Turkey, called in U.S. Ambassador Monteagle Stearns to deliver a protest on the issue today, on the eve of what may be the last round of talks on the future of the American military bases here.

The U.S. Embassy said the planes had followed normal procedures and acted in accordance with a previously agreed plan for the exercise, Reuter reported. The Greek protest did not refer to territorial airspace but to the much larger Athens flight information region, in which planes must alert Athens controllers before flying through.

U.S. special negotiator Reginald Bartholomew is expected back in Athens this weekend for the start of a new round of talks on the U.S. bases, after a three-week break. The opening of the new round was originally scheduled for May 16 but it was postponed, reportedly to allow Bartholomew time for further consultations in Washington.

Greece's protest brought banner headlines of a new bases-related crisis in Greek-U.S. relations today. The delay in Bartholomew's arrival similarly prompted press speculation on the fate of the six-month-old base talks last week.

Analysts saw today's Greek move as the latest act of political maneuvering by Prime Minister Andreas Papandreou. He is subject to growing domestic political pressure to resolve the uncertainty over the bases' future, but also is eager to minimize antagonism from the Communist opposition, and his own party's left wing, that would accompany reaching an agreement with Washington.

The strongly anti-American Greek Communist Party called on Papandreou earlier this week to stop negotiating and move unilaterally to close the bases.

The conservative New Democracy opposition, which tried unsuccessfully to renegotiate the 1953 agreement setting up the bases before losing power to the Papandreou's Socialists 18 months ago, has also launched what amounts to a put-up-or-shut-up assault on the prime minister.

Analysts say Papandreou, who is the chief arbiter of policy on the bases, is eager to wrap up the issue before Greece assumes the presidency of the European Common Market on July 1.

A $3 billion purchase of more than 100 military jets for the Greek Air Force, which is expected to include U.S.-made F16s, is thought to be heavily predicated on the economic returns from a new bases' agreement.

The two sides are believed now to be preparing to hammer out a formula for the time limits on a new agreement. Papandreou insists that this must include a specific termination date.

But it is not clear whether he would accept such a model as the U.S.-Spanish bases accord, which has a five-year termination date but allows for annual renewal afterward. The 1953 agreement is effective as long as both Greece and the United States remain members of NATO.