Pro-West Ukrainian citizens staged the biggest protest rally in Kiev since the 2004 Orange Revolution, demanding that the government sign a key pact with the European Union. The opposition called for the rally after President Viktor Yanukovych's government reversed a plan to sign a historic deal deepening ties with the European Union, in a U-turn that critics believe was forced by the Kremlin. Jailed Ukrainian opposition leader Yulia Tymoshenko has begun a hunger strike over a government decision to scrap a key EU pact that sparked huge protests. Her announcement came as President Viktor Yanukovych pleaded for calm after a second day of nationwide demonstrations over the move.