Russian advance has been halted in many directions, according to Ukrainian President Zelenskyy.

• In a speech translated by NBC News, Zelenskyy stated that the enemy has been halted in many directions, but the battles persist.
• According to a January report from the U.S. Congressional Research Service, Ukraine's army has approximately 145,000 to 150,000 troops.
• The military situation in Ukraine is constantly changing, and it is challenging to verify accurate information about it.

Despite renewed missile strikes at 4 a.m. local time, Ukraine's military has successfully stopped Russian invasion troops in most directions, according to Ukrainian President Volodymyr Zelenskyy.

Russia anticipates us to become weary, but we remain undeterred," Zelenskyy stated in a speech translated by NBC News. "The enemy has been halted in most directions, but the battles persist.

The military situation in Ukraine is constantly changing, and it is challenging to verify accurate information about it.

It's unclear how many of Russia's estimated 190,000 troops in the vicinity of Ukraine have crossed into Ukrainian territory.

According to a January report from the U.S. Congressional Research Service, Ukraine's army has approximately 145,000 to 150,000 troops.

Since 2014, low-level fighting has been ongoing in the eastern part of Ukraine, and many of its infantry soldiers have gained combat experience against pro-Russian separatists.

Thousands of reservists are reportedly being mobilized by the country.

On Friday, U.K. Defense Secretary Ben Wallace revealed on Sky News that Russia had suffered a significant loss of over 450 personnel, and their special forces had unsuccessfully tried to seize a crucial airport from Ukrainian defenders.

According to Wallace, as of this morning, our assessment is that Russia has not achieved any of its major objectives, and they are actually falling behind their planned schedule.

Air defenses

On Friday morning, Russian aircraft were spotted in Kyiv, but Ukraine's air defenses are functioning and safeguarding our skies, according to Zelenskyy.

On Friday, Kyiv experienced rocket attacks, as stated by its foreign minister. A live Reuters video feed depicted the city's streets largely vacant, with air raid sirens interrupting the silence.

A Russian aircraft reportedly struck a heavily damaged building in Ukraine, as shown in footage released by the State Emergency Service.

Zelenskyy stated on Friday that there were multiple explosions this morning. He emphasized that this is the same scenario that Ukraine faced in 1941. As the world's nations observe, Ukraine is defending itself independently.

In the 1940s, Ukraine witnessed intense battles against German forces.

— CNBC’s Victor Loh contributed to this report.