KIEV, Dec. 9 - The planned Ukrainian-Russian strategic cooperation agreement that would involve Ukraine's joining the Customs Union of Russia, Belarus and Kazakhstan and has triggered mass protests in Ukraine is due to be signed on December 17, a Ukrainian opposition leader claimed on Saturday.

"According to our information, [Ukrainian President Viktor Yanukovych] plans to sign it on December 17," Arseniy Yatseniuk, parliamentary leader of the Batkivschyna party, told a briefing at the "National Resistance Headquarters" in Kiev.