NATO has raised the readiness level of tens and thousands of troops amid soaring tensions with Russia, widely believed to be preparing to attack Ukraine.
NRF rapid reaction forces are to be able to be deployed within just 7 days, rather than 30, dpa learned from sources close to the alliance.
For other units, a "notice-to-move" period of 30 days applies, rather than 45 days, effective immediately.
The step seeks to deter Moscow from an attack, and comes as intense diplomatic efforts continue to prevent war from breaking out.
Western leaders adopted strategies from warnings to dialogue with Moscow on Friday, as tens of thousands of troops remained stationed along Ukraine's borders.
White House Deputy National Security Adviser Daleep Singh said Russia would be isolated from global financial markets and lose access to cutting-edge technologies in the event of an attack. "The cost to Russia would be immense," Singh said.
"If Russia invades Ukraine, it will become a pariah to the international community, it will become isolated from global financial markets, and it would be deprived of the most sophisticated technological inputs."
Russia would face the prospect of intense capital outflows, mounting pressure on its currency, surging inflation, higher borrowing costs, economic contraction, and the erosion of its productive capacity, he said, referring to the sanctions package prepared by the US and its partners.
At the same time, Washington is set to continue pursuing a dialogue, White House spokesperson Jen Psaki said late on Friday.
She said US Secretary of State Antony Blinken is to meet with his Russian counterpart Sergey Lavrov once again to discuss the Ukraine conflict on Wednesday.
The US still backs a diplomatic solution to the conflict but it remains unclear whether the Russians are serious about negotiating, Psaki said.
Tensions are soaring as up to 190,000 troops under Russian control surround Ukraine. The build-up began last year but more troops have been stationed in the region as part of exercises being held by Russia and Belarus.
Moscow has repeatedly denied plans to invade but has also demanded binding security guarantees of NATO, including that it will never admit Ukraine.
Meanwhile Moscow-backed separatists in eastern Ukraine urged civilians to flee across the border to Russia to protect themselves from an attack they claimed was imminent by Ukrainian government forces.
"Women, children and elderly people" should first be brought to safety, Denis Pushilin, the head of self-proclaimed Donetsk People's Republic, said in a video message. The Donetsk region alone was planning to evacuate 700,000 people, according to later information.
Pushilin said he was making an "urgent request" for residents to make a "mass, centralized departure," citing the threat of impending military action by Ukrainian troops.
Shortly afterwards, a senior official's car exploded in front of the government building in Donetsk, local media reported. No one was hurt, and it was unclear what caused the explosion.
The separatists in nearby Luhansk, the other rebel stronghold in Ukraine, also ordered similar measures.
Russian President Vladimir Putin said refugees fleeing a rumoured attack in eastern Ukraine should be given cash payments of 10,000 roubles (about $130).
Meanwhile Kiev reiterated its denials of any plans to attack the separatists.
Ukraine has no plans to launch an attack on separatist-controlled areas in its east, said the country's top military commander.
"An attack on the Donbass would irreversibly lead to countless victims among the civilian population, which is why such scenarios are not being considered at all," Valerii Zaluzhnyi said, arguing that Kiev seeks a peaceful solution to the problem.
"Don't believe the lies of the occupiers," he said, speaking directly to residents of the affected areas.
Other countries again said that Moscow was imperilling the region's security and issued pleas for calm.
Germany and France have called on Russia to use its influence on pro-Moscow separatists in eastern Ukraine to bring about a de-escalation in the burgeoning conflict.
They see no evidence for the separatists' accusations that a Ukrainian attack may be imminent, said a joint statement by Foreign Minister Annalena Baerbock and her French counterpart Jean-Yves Le Drian on Friday evening.
Russia should use its influence over the self-proclaimed republics and call for restraint, they said.
Their calls echoed similar demands for dialogue by German Chancellor Olaf Scholz and French President Emmanuel Macron on Friday.
The French and German foreign ministers also condemned the recent increase in ceasefire violations.
The Ukrainian army alleged Friday morning there had been almost two dozen violations by the rebels of the ceasefire agreed to in 2015 under Franco-German mediation. The claims could be not be independently verified.
Western powers have warned for weeks that the region could be on the precipice of war, saying the situation could escalate quickly and dramatically.
Russia has repeatedly denied having any intention of attacking its neighbour. The government condemns US, NATO and European assessments of the situation as distorted and an attempt to whip up anti-Russia "hysteria."
The situation in Ukraine is also in focus at the Munich Security Conference, where no Russian delegates are in attendance for the first time in years.
The Kremlin said instead, President Vladimir Putin would oversee military drills on Saturday involving the launch of ballistic and cruise missiles.
He also plans to join a manoeuvre to check Russia's nuclear arsenal, according to an announcement.
Belarusian ruler Alexander Lukashenko is also taking part, as both hold large-scale manoeuvre in the south of Belarus on Ukraine's border.
Lukashenko and Putin also discussed expanding their cooperation, and condemned the Western sanctions affecting both their countries.
Meanwhile Washington also said that Ukraine could expect further cyber-attacks if Russia were to invade the country.
Moscow was responsible for the recent cyber attacks on several Ukrainian websites, the US government said, referring to the sites of the Defence Ministry and several state-owned banks earlier this week.