Several U.S. foreign policy experts, including former ambassadors to Ukraine Steven Pifer and John Herbst, are calling for America to provide $3 billion in military assistance to Ukraine in the next three years. The group also called on other NATO members to provide lethal defensive weapons and equipment to reverse what they call an “urgent and deteriorating” situation in eastern Ukraine, where Russia has been waging war since April.

The experts say they reached their conclusion because of the failure of diplomacy alone to secure a peace agreement from Russian President Vladimir Putin, who is arming, financing and training the separatists in eastern Ukraine and supporting them with Russian troops.