(Reuters) - The loss of Malaysian Airlines flight MH17 must prove a catalyst for changing Russia's approach and ending the conflict in Ukraine, Prime Minister David Cameron wrote on Friday in an opinion piece in the New York Daily News.
Russia has been attempting to destabilise a sovereign state, violate its territorial integrity and arm and train thuggish militias, he wrote, and the world has paid the price.
Cameron has been pushing the European Union to impose harder-hitting sanctions on Russia after the downing of a Malaysian airliner in Ukraine, advocating an EU ban on future sales of military equipment to Moscow.
The 28-nation EU has been under pressure from the United States and Ukraine to take a harder line on Russia, but some EU governments are wary of potential retaliation from Moscow, the bloc's biggest energy supplier.
"Hurting Russia economically will carry some pain for our own economies too," Cameron wrote. "But serious economic measures are the only language that Russia will understand."
The European Union governments agreed on Thursday to add 15 people and 18 companies or other organisations to the bloc's sanctions list for undermining Ukraine's territorial integrity, diplomats said.
"It is time to make our power, influence and resources felt," Cameron wrote in the newspaper article.
"Together with America, Europe must do what is necessary to stand up to Russia and put an end to the conflict in Ukraine before any more innocent lives are lost."
(Reporting by Supriya Kurane in Bangalore; Editing by Clarence Fernandez)