NATO Secretary-General Jens Stoltenberg has called for continued diplomatic pressure and sanctions on Russia until Moscow respects a February 2015 agreement aimed at ending the conflict in eastern Ukraine.
"The international community must keep pressuring Russia to respect its obligations, especially while the security situation in eastern Ukraine remains so serious," Stoltenberg said after talks with NATO and Ukraine foreign ministers in Brussels on December 7.
"I believe sanctions are an important tool to send a very clear message that we do not accept the kind of aggressive behavior -- the illegal annexation of Crimea and the destabilizing behavior in eastern Ukraine -- which Russia is responsible for," Stoltenberg added.
Stoltenberg's comments on the need for renewing sanctions on Russia come amid doubts about their effectiveness and cost, and fears that U.S. President-elect Donald Trump may take a more conciliatory line with Moscow.
Trump, who is set to succeed outgoing President Barack Obama in January, has spoken positively about Russian President Vladimir Putin, expressing a desire to mend battered bilateral ties with Moscow and saying he would examine the possibility of lifting sanctions targeting Russia in response to its actions in Ukraine.
Separately, German Foreign Minister Frank-Walter Steinmeier said he expected EU leaders to prolong sanctions on Russia when they meet in Brussels next week.
EU President Donald Tusk also said last month he was confident the sanctions would be approved before an EU leaders summit on December 15.
Stoltenberg said there was a "massive increase in cease-fire violations" in Ukraine’s east, where fighting between government forces and Russia-backed separatists has killed more than 9,600 people since April 2014.
He said hundreds of explosions are sometimes reported daily, including many caused by heavy weapons banned under the Minsk peace accords.
Last week, a meeting of foreign ministers from Russia, Ukraine, France, and Germany intended to shore up the peace process ended without new breakthrough.