Sea Breeze 2008, a NATO military exercise, began last Monday in Ukraine's Odessa, Crimea and Black Sea coastal regions. Two years ago, the Sea Breeze 2006 exercise in the Crimea was also disrupted by protests.
Ukraine and the United States are joined by 15 other countries for this year's exercises, which are due to end on July 26. Fifteen Ukrainian ships, four aircraft, 10 helicopters, and 500 service personnel are involved in the military exercises.
"On the morning of July 21, 10 Brotherhood boats blocked off the exit from the port of Odessa, where foreign warships are deployed, with the aim of preventing them from participating in the NATO Sea Breeze 2008 exercise," the party said.
It added that three boats were later detained, but the others continued the 'blocking operation.'
"The NATO drill in Odessa is being accompanied by numerous protests by local residents. This demonstrates the public mood in Ukraine over the government's course toward early admission to the alliance," it said.
In May and June, several Ukrainian left-wing politicians announced that they would organize mass protests to disrupt the drills. Last Thursday, some 20 opposition activists set up a camp in western Crimea, intending to picket the exercises.
A branch of the Ukrainian Communist Party in Donetsk said over 1,000 people had taken part in anti-NATO rallies in the Donetsk Region in eastern Ukraine.
The Ukrainian Progressive Socialist Party said on Wednesday that authorities in the Odessa region had banned broadcasts by Russian television channels over their coverage of the exercise and the accompanying protests.
Ukraine's pro-Western leadership has been pursuing NATO membership since 2004, when President Viktor Yushchenko came to power. Ukraine failed to secure a place in the NATO Membership Action Plan, a key step toward joining the alliance, at a NATO summit in April, but was told the decision would be reviewed in December.
A poll conducted in April by the FOM-Ukraina pollster indicated that a majority of Ukrainians oppose NATO membership.