Russian troops have reached the outskirts of Kyiv after launching a full-scale invasion of Ukraine from three main directions.

Troops are advancing from the north; from the east through Donetsk, Luhansk, Kharkiv and Sumy; and from Crimea in the south.

Dozens of targets have been struck, as Russian troops have poured into Ukraine.

The fight for Kyiv

On Friday, Russian troops arrived in the Obolon area of the north of the city, according to Ukrainian officials.

Reports suggest that the main Russian advances are towards the city centre from Ivankiv to Kyiv’s north west and Chernihiv to the north east.

Ukraine’s capital has come under further missile attack as Russian troops approach from the north.

Gunfire has been heard in the central government area of the city centre near the presidential office.

The Ukrainian army says it has blown up a bridge over the Teteriv river at Ivankiv, 50 miles (80km) to the north of the city, to slow the Russian advance.

There has been fierce fighting at Antonov airport, to the west of Kyiv. Yesterday airborne Russian troops attacked the airport at Gostomel.

Russian troops around Ukraine

Russia is now in full control of significant parts of Ukraine’s territory.

After Ukraine’s air defences and other military infrastructure came under attack on Thursday, columns of tanks have moved rapidly into position, backed up by artillery and air power.

Among the initial targets were Kyiv, Karkhiv, Odesa and Ivano-Frankivsk.

Troops are now spreading out in parts of the north, east and south, with missile strikes and artillery clearing the way for advancing Russian forces.

Strike from the north

From the north, Russian troops are believed to have crossed the border into Ukraine at the three-way junction between Ukraine, Russia and Belarus, at Senkivka.

In recent weeks, a huge deployment of Russian troops has gathered close to Novye Yurkovichi and Troebortno, including “the entire 41st army”, according to Michael Kofman of the US-based Center for Naval Analyses.

Armoured columns, including tanks and multiple launch rocket systems, moved through Chernihiv, on a direct path to Kyiv.

A second advance has come down the west side of the Dnieper river via Chernobyl.

Strike from the east

There is also fighting around Donetsk, which has come under attack from troops crossing from Belgorod in western Russia.

Separately, Russia’s Interfax news agency reported claims from Russian-backed separatists that they had launched an offensive on the Ukrainian-controlled town of Shchastia in Luhansk.

There was also fierce fighting around Sumy, near Kharkiv.

There are thought to be about 15,000 Russian-backed separatists in Donetsk and Luhansk, who may help a Russian advance. Ukraine believes the figure is higher.

Strike from the south

In the east, there has been fighting around Kharkhiv, Ukraine’s second-largest city. Parts of the city have been shelled.

In the south, troops have crossed from from Crimea to the mainland, towards Kherson, taking Chongar and Novo Alekseyevka.

Explosions have been heard in cities across the region, including Odesa, Mariupol, Melitpol and Kherson.

On Thursday, Ukrainian officials – quoted by the Reuters news agency – said Russian troops had landed in the ports of Odesa and Mariupol.

In recent days, Russia had positioned landing ships capable of deploying main battle tanks, armoured vehicles and personnel, off the Ukrainian coast in a major build-up in the Black Sea and the Sea of Azov.

Ukrainian forces are concentrated in the east of Ukraine, towards Donetsk and Luhansk,

Ben Barry, of the International Institute for Strategic Studies, says that a Russian advance north from Crimea may succeed in cutting them off from Kyiv, stranding them on the east side of the Dnieper River.

With Russian troops to their east, in Donetsk and Luhansk, north in Russia, and on the west bank of the Dnieper, they would be encircled.