Bad weather has delayed by one day the joint naval exercise of U.S., Bulgarian and Romanian naval forces in the Black Sea, a statement by the Bulgarian defence ministry said on Tuesday.
A U.S. navy destroyer was due to take part in manoeuvres with Romanian and Bulgarian warships in the Black Sea across the water from the Crimean Peninsula where Russian military groups have seized control from Ukrainian authorities.
To the north in Poland, U.S. fighter jets are also to take part in joint exercises, with Poland's president expected to review the manoeuvres.
The United States stressed that both training drills were planned before the Ukraine crisis, but they are also a signal of support for NATO members nervous that if Russia is prepared to intervene in Ukraine, they could be next.
Reporting by Tsvetelia Tsolova