WASHINGTON, Feb. 9 - U.S. President Barack Obama made clear he was some way from a decision on whether to arm Ukraine in its conflict against Russian-backed rebels, saying on Monday he still hoped for a diplomatic solution, Reuters reported.

"The measure by which I make these decisions is: 'Is it more likely to be effective than not?'," Obama said at a news conference with German Chancellor Angela Merkel, who opposes providing Ukraine with weapons to fight separatists in its east.

Russia had violated a September peace deal by sending more tanks and artillery into eastern Ukraine, Obama said, adding that he and Merkel had agreed sanctions must stay for now and Moscow's isolation would worsen if it continued on its current course.

Merkel is due to meet Russian President Vladimir Putin and Ukrainian President Petro Poroshenko on Wednesday with French President Francois Hollande, and European Union ministers held off tightening sanctions on Monday to give the talks a chance.

Merkel and Obama have come under fire from U.S. foreign policy hawks in the Republican-controlled Congress who want weapons sent to the Ukraine army.

The U.S. Senate and House unanimously passed legislation in December that authorized sending arms for Kiev. Obama signed the measure into law but it gave him leeway over whether or when to implement it.

Congressional aides said on Monday lawmakers were working on legislation that would commit Obama to providing arms.

"The Ukrainians are being slaughtered and we're sending them blankets and meals," Sen. John McCain said at a security conference in Munich at the weekend. "Blankets don't do well against Russian tanks."

Nine Ukrainian troops were killed in a 24-hour period over Sunday and seven civilians also died, Kiev said on Monday, with fighting particularly intense around the town of Debaltseve, a major rail and road junction northeast of the city of Donetsk.

But Merkel made clear in Munich her opposition to arming Kiev. "I understand the debate but I believe that more weapons will not lead to the progress Ukraine needs. I really doubt that," she said.

Obama has to decide whether to supply weapons, impose tougher sanctions on Russia in the hope of forcing Putin to compromise, or throw his full weight behind the revised German-French peace initiative.
He said his decision would not rest on a specific point.

"Can we be certain that any lethal aid that we provide Ukraine is used properly, doesn't fall into the wrong hands, does not lead to over-aggressive actions that can't be sustained by the Ukrainians? What kinds of reactions does it prompt, not simply from the separatists but from the Russians? Those are all issues that have to be considered," he said at the White House. (rt/ez)