The White House says U.S. President Barack Obama is expected to sign legislation implementing new sanctions on Russia over its activities in Ukraine by the end of the week.
Press Secretary Josh Earnest made the announcement on December 16 in Washington.
Congress passed the bill on December 13, authorizing new sanctions against Russia's defense and energy industries, including the arms exporter Rosoboroneksport, and investors in its high-tech oil projects.
It also authorizes -- but does not technically require -- $350 million of defense articles for Ukraine's military, including antitank and antiarmor weapons, ammunition, and surveillance drones.
The White House has thus far declined to fulfill Kyiv's request to provide lethal aid.
The announcement came as U.S. Secretary of State John Kerry said Russia had made "constructive moves" in recent days over the conflict in Ukraine.
Speaking in London on December 16, Kerry reiterated that Western sanctions against Russia were introduced to prompt Russia to stop its interference in Ukraine.
He added that the West did not seek to "hurt the people of Russia" and said that sanctions against Russia "could be lifted in a matter of weeks or days, depending on the choices that President [Vladimir] Putin takes."
Kerry said he hoped progress with Russia in their talks about the crisis in Ukraine would continue.
He added that Washington was following the decline in the value of the Russian ruble, which he said had been affected both by Western sanctions against Russia and by falling world oil prices.
Meanwhile, Russian Foreign Minister Sergei Lavrov reiterated in Paris on December 16 that there were "very serious reasons" to think Western sanctions are aimed at regime change in Moscow.
Lavrov also spoke to the French broadcaster France 24 about sanctions on his country, admitting it is hurting Russia, but adding, "I can assure you that Russia would not only survive but would come out stronger out of this."
Surprisingly, Lavrov voiced cautious praise for Ukrainian President Petro Poroshenko, saying that "Poroshenko is the best chance at this point in Ukraine."
Lavrov said he was "carefully optimistic" about the chances for peace in Ukraine, but at the same time Russian news agency Interfax quoted the Russian foreign minister as saying that while the Kremlin was in favor of Ukraine preserving its territorial integrity, Kyiv must accept that Crimea is part of Russia now.
Meanwhile, during a visit to Brussels to meet with European Union and NATO officials, Ukrainian Prime Minister Arseniy Yatsenyuk said Crimea was part of Ukraine and expressed concerns that Russia could deploy nuclear weapons there.
"Russia is constantly violating international law," Yatsenyuk said, and claimed "Russia started to violate nuclear nonproliferation treaties" signed in 1994 when the United States, Britain, and Russia agreed to keep Ukraine free from nuclear weapons.
In Kyiv, European Union foreign-policy chief Federica Mogherini said the 28-nation bloc, which has also imposed sanctions on Russia, intended to "walk hand-in-hand" with Kyiv.
Speaking to Poroshenko during her first visit to Ukraine since her August appointment, Mogherini said, “We will continue to stay in Ukraine, making sure that this conflict comes to an end with the full respect of Ukrainian sovereignty and territorial integrity."
Mogherini’s visit comes ahead of an EU summit on December 18 in which Ukraine and the bloc's relations with Russia are likely to top the agenda.
Late on December 16, the Elysee Palace said French President Francois Hollande and German Chancellor Angela Merkel held a four-way telephone call with Putin and Poroshenko.
It said Hollande and Merkel called for a rapid resumption of contacts under the September cease-fire agreement, stressing the importance of “moving forward without losing any more time."
A new cease-fire with pro-Russian rebels was declared by Kyiv last week in hopes of ending an eight-month conflict that has claimed at least 4,700 lives and displaced close to 1 million people, according to the United Nations.
Poroshenko said on December 16 that the military situation in eastern Ukraine was quiet, with no shelling reported.
But a top Ukrainian military commander said later in the day that up to 10,000 Russian soldiers and their heavy weapons are still deployed in rebel-held eastern Ukraine despite the new cease-fire.
General Staff commander Viktor Muzhenko told reporters, "The number of soldiers of the Russian Federation is between 6,000 to 8,000, though according to some sources it is up to 10,000."
Muzhenko said close to 50,000 Russian soldiers were also stationed along Ukraine's eastern border, where heavy weaponry has continued to flow in since the December 9 truce started.
A fresh round of peace talks between representatives from Ukraine, Russia, the two pro-Russian separatist regions in eastern Ukraine, and the EU were tentatively due to be held in Minsk last week but have been continually postponed.
With reporting by Reuters and AFP