The Russian blitz has pushed the U.S. to accelerate its "security plan" for Ukraine.
Kyiv declared that talks with the U.S. on "security guarantees" would start this week.
The U.S. security arrangements "are said to stay in place" until Ukraine joins NATO.
The talks come as Ukraine fails to stop Russia despite enormous western weapons.
Russia is closely monitoring the new U.S.-Ukraine "security plan" amid a raging war.
Moscow has warned both the U.S. and Ukraine against any anti-Russia plot.