(Edits, updates with Czech defence ministry)
WARSAW/WASHINGTON, March 21 (Reuters) - The United States and Poland are looking at the possibility of including other NATO member states from eastern Europe in joint aviation activities at a Polish air base, U.S. officials said on Friday.
The expansion of the manoeuvres, if it goes ahead, would be the latest in a series of calibrated steps the Pentagon has taken to make its presence in eastern Europe more visible since the Russian military intervened in Ukraine's Crimea Peninsula.
Russia's actions have made some NATO members in former communist central Europe anxious that they could be next in line, prompting Washington to reassure them that it will protect them if needed, in line with NATO security guarantees.
The U.S. and Polish air forces have this month been carrying out joint exercises based around the Lask air force base in central Poland.
Stephen Mull, U.S. ambassador to Poland, said discussions were underway on possibly expanding the scope of those exercises in the future.
He mentioned the Czech Republic, Hungary, Slovakia, Romania, Bulgaria and the Baltics, as the NATO countries that might be involved if the exercises were expanded.
A U.S. military official said a report by Poland's ZET radio station that the enlarged exercises were already being prepared had "mischaracterized" the ambassador's remarks.
"To summarize, he stated that the Poles and the U.S. are talking about the possibility of expanding aviation activities at Lask to potentially include other NATO partners, and then he mentioned those nations," said the official.
The Czech defence ministry issued a statement saying its officials were in talks with foreign partners on a joint military exercise involving the United States, Poland and the Czech Republic. (Reporting by Anna Wlodarczak-Semczuk in Warsaw, Phillip Stewart in Washington and Robert Muller in Prague; Editing by Gareth Jones)