The incident occurred as a US guided-missile destroyer The
Truxtun began a one-day exercise with the Bulgarian and Romanian
navies in the Black Sea.
Military officials said it was a "routine" deployment scheduled
before the crisis, but it comes after the US also recently deployed
jet fighters to bolster Nato forces in Eastern Europe.
US Naval Forces Public Affairs Officer Shawn Eklund said: "There
are many reasons for exercises with allies, it allows us an
opportunity to reassure our NATO allies that we support them."
Mr Putin yesterday signed a treaty to incorporate Crimea into
Russian territory following a referendum in the region which
overwhelmingly backed the move.
Jubilant crowds in Moscow hailed the annexation, while Ukraine's
new government in Kiev called the Mr Putin a threat to the
"civilised world".
However, the Kiev government still sent the first Deputy Prime
Minister and acting Defence Minister to fly to Crimea this morning
to "resolve the situation".
Senior minister Ostap Semerak told a meeting of the cabinet that
Vitaly Yarema and Ihor Tenyukh would be charged with "ensuring the
conflict does not become military in nature".
Ukraine's military experts inspected Russian operations in
Belgorod and Kursk regions under an international agreement. The
four Ukrainian military specialists monitored around 13,000 square
kilometres by helicopter to check for "undeclared military
activity".
Thousands of Russian troops took control of Crimea two weeks
before Sunday's hastily called referendum, seizing Ukrainian
military bases, blockading others and pressuring Ukrainian soldiers
to surrender.
The United States and the European Union on Monday imposed
sanctions on Russia, targeting Russian and Crimean officials with
visa bans and asset freezes.
