The United States and the Great Britain are promising to maintain pressure on Russia over its intervention in Ukraine.
U.S. President Barack Obama and British Prime Minister David Cameron made the pledge in a joint opinion article in the January 15 edition of the Times of London ahead of two days of meetings in Washington, the Times report.
The United States, the European Union, and other nations have imposed a series of sanctions on Russia over its annexation of Crimea last March and its support for separatists in East Ukraine.
"Our strong and united response has sent an unmistakable message that the international community will not stand by as Russia attempts to destabilize Ukraine," Obama and Cameron wrote.
"If we allow such fundamental breaches of international law to go unchecked, we will all suffer from the instability that would follow," they wrote.
Obama and Cameron are to have a working dinner on January 15 and hold more talks on January 16.