Gen. Philip M. Breedlove attends a media conference at NATO headquarters in Brussels last month. (Geert Vanden Wijngaert/AP)

The fighting in eastern Ukraine is “getting worse every day” and Western efforts to deter Russian intervention are having little effect, NATO’s top military commander said Wednesday.

In appearances on Capitol Hill and at the Pentagon, Air Force Gen. Philip M. Breedlove, the commander of U.S. and NATO forces in Europe, gave a decidedly pessimistic account of the Ukrainian conflict. He also predicted that Russia’s success in destabilizing Ukraine would embolden President Vladi­mir Putin to sow divisions elsewhere as part of a strategy to weaken NATO politically and expand Moscow’s influence in the region.

With the Obama administration wrestling with the question of whether to respond more aggressively by providing arms to the Ukrainian government, Breedlove acknowledged that such a move would be a gamble. “I can’t tell you what is going on inside Mr. Putin’s head,” he said, adding that U.S. officials are unsure whether sending arms to Kiev would cause Russia to back down, or escalate the war.

“We have to be cognizant that if we arm the Ukrainians, it could cause positive results. It could cause negative results. But what we’re doing right now is not changing the results on the ground,” he said during testimony before the House Armed Services Committee.

Later, during a press conference at the Pentagon, Breedlove said he has submitted formal recommendations to the White House, via his chain of command at the Pentagon, on what other measures Washington should take to push back against Moscow and its support for pro-Russian rebels in eastern Ukraine.

Although he declined to elaborate on his proposals, Breedlove said that in order to turn the tide in Ukraine, the United States and its NATO allies need to develop a more effective mix of diplomatic, military and economic tactics.

“We don’t want a war of grand proportions in Ukraine. We must find a diplomatic and political solution,” he said. “What is clear is that this is not getting better. It is getting worse every day.”

Obama administration officials have said they are weighing a new round of economic sanctions against Russia as well as whether to send anti-tank missiles and other weaponry to Ukraine. Until now, Washington has limited its military assistance to non-lethal aid, such as body armor, night-vision goggles, radios and uniforms.

There is rising bipartisan support in Congress for the idea of arming the Ukrainians, with many lawmakers criticizing Obama for being too cautious. But some influential NATO allies, including Germany and France, have resisted the idea, arguing that it would only make matters worse.

“We have to be absolutely straightforward to say that none of us knows what Mr. Putin will decide,” Breedlove said. “If we take action, many believe he’ll accelerate. If we take action, others believe it may raise the cost to him, and he might make another decision.”

In general, Pentagon officials are believed to favor a more aggressive approach. At his confirmation hearing this month, Defense Secretary Ashton B. Carter said he was “inclined” to support arming Ukraine’s government.

On Wednesday, Breedlove also downplayed the idea that Putin would “up the ante” if Washington delivered weapons to Kiev. He noted that the Russian government has already sent combat forces into eastern Ukraine, including artillery battalions and sophisticated air defenses.

“I would say that Mr. Putin has already set the bar and the ante very high,” he said.