-LRB- CNN -RRB- -- Lawmakers in Ukraine scuffled with each other , throwing punches and eggs , as parliament met Tuesday to ratify a treaty with Russia that extends the latter 's navy presence in the Ukraine 's Crimean peninsula until 2042 . The ruling Regions party eventually ratified the treaty but not before howls of protest from the opposition . Someone set off a smoke bomb inside the building , while Speaker Volodymyr Lytvyn sought refuge behind an umbrella as he was pelted with eggs . During a rally attended by thousands on Saturday , opposition leader Yulia Tymoshenko -- the former prime minister who lost to Viktor Yanukovych in the presidential election run-off in February -- said the ratification must be prevented at all costs . She claimed that Yanukovych is `` selling out '' Ukraine , has `` openly embarked on the path of destruction of -LRB- Ukraine 's -RRB- national interests , and has actually begun the process of eliminating the state 's sovereignty . '' The deal was signed last week by Yanukovych and Russian President Dmitry Medvedev . Tymoshenko said it violated part of the Ukrainian Constitution , which forbids the country from hosting foreign military bases after 2017 . The deal extends Russia 's lease of a major naval base in the Black Sea port of Sevastopol for an additional 25 years , in exchange for a 30 percent cut in the price of natural gas that Russia sells to Ukraine . The agreement may bring an end to years of disputes over natural gas prices , which culminated in Russia turning off the pipeline to Ukraine . The dispute affected not only Ukrainians , but many Europeans who depend on Russian gas pumped through Ukraine . The two countries had been at odds ever since the `` Orange Revolution '' swept Yanukovych 's fiercely anti-Russian predecessor Viktor Yushchenko to power in 2005 . Throughout his time in office , Yushchenko repeatedly threatened to expel Russia 's Black Sea Fleet from Sevastopol . The Russian military lease there was scheduled to expire in 2017 . Yanukovych said the new deal added a `` concrete and pragmatic dimension '' to centuries of relations between Ukrainians and Russians . Opposition groups in Ukraine , however , were quick to denounce the agreement . Yuschenko 's `` Our Ukraine '' party said the treaty would lead to the `` Russification '' of Ukraine .