U.S. President Barack Obama's nominee to fill the number two post at the State Department says the White House should consider providing Ukraine with lethal, defensive military equipment.
Testifying Wednesday before the Senate Foreign Relations Committee, Tony Blinken said that arming Ukraine's military could force Russia to rethink its role in the conflict gripping eastern Ukraine.
Both houses of Congress have voiced support for such aid, but the Obama administration has so far stopped short of providing lethal equipment.
The Kyiv government and a host of Western nations have accused Moscow of providing direct aid, including armor and other military hardware, to separatists. NATO also has accused Moscow - which annexed Ukraine's Crimea Peninsula in March - of sending more tanks and troops into eastern Ukraine in the past two weeks.
The Kremlin has repeatedly denied direct involvement, and says Russian soldiers fighting alongside rebels in eastern Ukraine are doing so as volunteers and on their own time.
Earlier Wednesday, Russian Foreign Minister Sergei Lavrov urged the Kyiv government to hold direct negotiations with separatists. However, Ukrainian officials quickly rejected the idea.
Lavrov also referred to the Kyiv leadership as "the party of war," and said Western moves to exclude rebels from peace talks will prove "absolutely counterproductive and provocative." He also said efforts to paint Russia as a party to the conflict will ultimately fail.
In Kyiv, Ukraine's Prime Minister Arseniy Yatsenyuk again said his government will not hold talks with whom he called "Russian terrorists."
Separately Wednesday, German Foreign Minister Frank-Walter Steinmeier said rebels and the Kyiv government were, in his words, "unfortunately still a long way from a sustainable de-escalation of the conflict, and even further from a political solution."
Steinmeier spoke in Berlin after face-to-face talks Tuesday with Russian President Vladimir Putin in Moscow.
According to figures from the United Nations, the conflict in eastern Ukraine, which started in April, has to date claimed more than 4,100 lives and left nearly 10,000 wounded.