The Ukrainian opposition will ask the European Parliament to extend the monitoring mission of Pat Cox and Aleksander Kwasniewski, says Arseniy Yatseniuk, the leader of the Ukrainian opposition parliamentary faction Batkivschyna.

"We ask the European Parliament and our European partners to extend the Cox-Kwasniewski mission in Ukraine," Yatseniuk told journalists on Thursday in Vilnius, where he is taking part in a civil society conference.

Ukraine will sign an association agreement with the EU sooner or later, Yatseniuk said. "This is exactly why we are urging our European partners to keep the door open," he said.

Cox pointed out to journalists that Ukraine, as a sovereign country, decided to take a break in its preparations for signing an association agreement with the EU. He said he had no doubts that the EU would keep the door for Ukraine open and top-level contacts would continue.

Cox, a former European Parliament president, and Kwasniewski, a former Polish president, were assigned first to monitor the trials of former Ukrainian Prime Minister Yulia Tymoshenko and started their mission on June 11, 2012. Their mandate was later extended.

The Cox-Kwasniewski monitoring mission was extended on November 13 until the European Partnership summit in Vilnius, which is opening on Thursday.