The conflict continues after the invasion was announced by President Vladimir Putin in a televised address yesterday morning (February 24).
However, explosions have been heard in the capital and across the country.
Russian forces captured the former nuclear power plant in Chernobyl.
Here is everything you need to know about the capital of Ukraine:
Is it Kiev or Kyiv?
The capital’s Ukrainian name, when written in the Ukrainian Cyrillic Alphabet, is Ки́їв.
When Ки́їв is transliterated into the Latin alphabet, it is regularly referred to as Kiev or Kyiv.
Kiev was the historic English-language name for the city but its usage is now easing as it is based on a historical Russian derivation of the name.
The conflict between Russia and Ukraine has encouraged a shift to the official romanised title of Kyiv.
When did the capital change its name?
When Ukraine became independent in 1991, new regulations were introduced to change place names from the Cyrillic alphabet to Latin.
Following the independence, the spelling Kyiv was legally approved by the Ukrainian government in 1995.
In the English language, Kiev has also now changed to Kyiv.
However, the title of Kyiv became a controversial issue in 2014.
In this year, pro-Russian Viktor Yanukovych was ousted and the new administration began to seek closer ties with NATO and the EU.
In 2018, the Ukrainian Ministry of Foreign Affairs launched a campaign called 'KyivNotKiev' in a hope that the spelling would be adopted internationally.
The campaign targeted embassies, international media, and airports that were still using the spelling of 'Kiev' instead of 'Kyiv'.
The ministry stated: 'Ukraine has been an independent sovereign nation for more than 27 years, but the Soviet-era versions of many geographic names stubbornly persist in international practice.
‘The usage of Soviet-era place names – rooted in the Russian language – is unacceptable to the people of Ukraine.’
Which title is more commonly used?
The US and UK governments embrace the spelling of Kyiv and they have been joined by media outlets such as the BBC, The New York Times, and The Wall Street Journal.
Changes have also been made by the Associated Press and Guardian style guides.
The Associated Press said: ‘Although the AP prefers traditional English spellings for many cities, including Rome, Moscow and Warsaw (not Roma, Moskva, and Warszawa), we regard the Ukrainian spelling of Kyiv as an important adaptation because it is linked to Ukraine’s present status.
‘To many Ukrainians, the former spelling Kiev appears outdated because it is associated with a time when Ukraine was part of the Russian and Soviet states, rather than an independent country.’
How to pronounce Kyiv
The pronunciation of Kyiv is different from the Russia-derived title for the capital.
In English, Kiev was pronounced as key-ev but the correct way to say Kyiv is kee-eve.
Where is Kyiv on the map?
Kyiv is located in north-central Ukraine and the capital lies along the Dnieper River.
The city covers an area of 300 square miles on both banks of the river.
Kyiv is approximately 500 miles south-west of Moscow, which is the capital of Russia