Opposition lawmakers in Ukraine threw eggs and set off a smoke bomb during a chaotic parliamentary vote Tuesday on extending Russia's lease of a Crimean naval port for the Black Sea Fleet.
The eggs were thrown at the speaker, who was forced to take cover under umbrellas unfurled by aides.
Politicians then scuffled in the aisles of the chamber, shoving, grabbing and punching each other next to a giant Ukrainian flag that was draped over the seats.
At one point, someone set off a smoke bomb, which engulfed the chamber in a thick haze even as lawmakers continued to fight.
The measure is also up for ratification in the Russian parliament, where a far more orderly session is under way on the same day.
The countries' presidents agreed last week to extend the Russian navy's use of the Sevastopol port for another 25 years after the old lease expires in 2017.
The deal is the most concrete sign of Russia's renewed influence in Ukraine since Viktor Yanukovych became president in February.
Yanukovych replaced Viktor Yushchenko, who adamantly pushed to move Ukraine out of Moscow's shadow and integrate more closely with Western Europe.
Opposition lawmakers in Ukraine submitted a draft bill on Monday to reverse last week's deal, which was the clearest sign yet of the new cohesion between Moscow and Kiev since Russia-friendly President Viktor Yanukovych took power in February from his Western-leaning predecessor.
In return for allowing the Russian navy to remain in the Ukrainian port of Sevastopol until 2042, Russia agreed to large discounts on gas.
Several thousand Ukrainians led by former Prime Minister Yulia Tymoshenko rallied in front of parliament on Saturday to protest the naval base deal.
Tymoshenko and other opposition leaders said the deal amounted to ceding control over the nation's territory, and have called on all opposition forces to unite to resist the deal she denounced as an "unprecedented step of national treason and shame."