U.S. President Barack Obama and European leaders were to hold a video conference on Tuesday to discuss the Ukraine crisis and global security issues, the White House said.
Obama and the leaders of Britain, France, Germany and Italy, as well as the head of the European Council, were set to participate in the talk, it said in a statement.
The planned virtual meeting overlapped a speech before a joint session of Congress by Israeli Prime Minister Benjamin Netanyahu, whose appearance stirred controversy because it was orchestrated by Obama's rival Republicans.
The video conference comes amid continuing violence in Ukraine despite a two-week-old ceasefire agreement, as leaders weigh the role for observers and peacekeepers and the possibility of further sanctions on Russia for supporting Ukrainian rebels.
The United States has also said it is still considering the possibility of sending Kiev defensive weapons.
Ukraine and Western governments have accused Russia of sending troops and weapons to support separatists in eastern Ukraine despite the peace deal reached on Feb. 12. Moscow has denied providing such support.
On Tuesday, Kiev announced its highest casualty toll in several days, with three Ukrainian servicemen dead and nine wounded amid pro-Russian shelling.
European leaders on Monday said they agreed that the Organization for Security and Cooperation in Europe (OSCE), a European rights and security watchdog, needed a broader role as observers of the ceasefire agreement and of the removal of weapons.
Later this week, Ukraine's parliament is expected to back Ukrainian President Petro Poroshenko's request for international peacekeepers to monitor the conflict. That idea, however, has faced a chilly reception in Europe.
British Prime Minister David Cameron, French President Francois Hollande, German Chancellor Angela Merkel and Italian Prime Minister Matteo Renzi will hold the call with Obama, who will be in the White House Situation Room. European Council President Donald Tusk will also participate, the White House said.
The United States and Europe have already imposed sanctions on Russia over its actions in Ukraine, and the United States has warned Russia over its support of the separatists despite the deal.
European leaders, who spoke with Tusk in late February, have also discussed further sanctions on Russia over Ukraine.