New Delhi, Feb 24 (IANS): Residents of Kharkiv, Ukraine's second largest city, said on Thursday that windows in apartment blocks were shaking from constant blasts as the Ukrainian military and Russian forces exchanged shellfire, BBC reported.

Clashes have also been taking place around the capital Kiev in the north and the Black Sea port cities of Odesa and Mariupol in the south, the report said.

Air strikes from Russia have been carried out on Ukrainian military bases and airports, with fierce fighting reported around a key airport near Kiev.

The Ukrainian military claims to have shot down at least six Russian aircraft, while Russia claims to have destroyed more than 70 military targets in Ukraine, BBC reported.

Many Ukrainians are seeking shelter or trying to leave larger cities around the country, including thousands seen fleeing Kiev.

Soon after Russian President Vladimir Putin declared the beginning of the invasion of Ukraine, videos and images claiming to be from the conflict zones began trending on major social networks.

While there are many genuine footage, some viral clips racking up hundreds of thousands of views show events from past conflicts or old military exercises. Many of these seem to coming from users posting content without checking, BBC reported.

The BBC has seen videos of the 2014 Russia-Ukraine war, the 2011 Libyan war and the 2020 Beirut explosions going viral.

In one example, a former Ukrainian ambassador to the US tweeted a video which he claimed was taken in Mariupol, but a version of the same clip was uploaded on TikTok weeks ago, apparently showing a lightning hitting a power station, the report said.

Another viral video claiming to show Russian military paratroopers landing in Ukraine first appeared online in 2016, BBC reported.