KIEV, Ukraine — Several thousand Ukrainians rallied in front of parliament Saturday to protest a deal allowing Russia to keep its navy in Ukraine for another 25 years. Former Prime Minister Yulia Tymoshenko told the protesters that all opposition forces must unite to resist the deal signed earlier this week which she denounced as an "unprecedented step of national treason and shame." The agreement signed Wednesday is the first concrete sign that newly-elected President Viktor Yanukovych will steer Ukraine back into Russia's orbit, reversing his pro-Western predecessor's attempts to decrease Moscow's influence. The pact allows Russia to extend its lease of the Black Sea Port of Sevastopol for another 25 years after the current lease agreement expires in 2017. Russia immediately rewarded Yanukovych by giving the ex-Soviet republic steep discounts for the natural gas. Tymoshenko and other opposition leaders said the deal amounted to ceding control over the nation's territory.