Ukrainian President Petro Poroshenko says he "doesn't have a slightest doubt" that the United States will send weapons to his country to help it fight pro-Russian rebels.

Government forces have been fighting Russia-backed separatists in eastern Ukraine for 10 months in a conflict that has left 5,300 people dead.

U.S. President Barack Obama has opposed sending lethal assistance to Ukraine's government, but a senior administration official told The Associated Press earlier this week the surge in fighting has spurred the White House to review the policy.

German Chancellor Angela Merkel on Tuesday said that she was opposed to the idea.

Poroshenko said on a visit to a government-controlled city in eastern Ukraine on Wednesday that it "needs the capabilities to defend itself."