Western sources said the Russian troops were struggling with logistical supply problems and their failure to control Ukraine's airspace, while Ukrainian forces were hitting back with counterattacks of their own.

Here is a summary of the situation on the ground, based on statements from both sides, Western defence and intelligence sources and international organisations.

- The east -

The major northeastern city of Kharkiv is encircled but Russian troops have failed to take it, instead subjecting the centre of the city to heavy bombardments from the air and artillery.

Russian strikes demolished the six-storey building of a higher-education institution in Kharkiv, killing one person and leaving another trapped in the wreckage.

The city of Sumy further to the north and close to the Russian border is also encircled.

- Kyiv and the north -

Kyiv remains under Ukrainian control despite heavy bombardments, but observers say Russian forces are still seeking to advance towards the capital.

The UK defence ministry said that Ukrainian forces' resistance was continuing to frustrate Russian attempts to encircle the city and the Russian advance had overall made "minimal progress" this week.

Authorities in Kyiv said one person was killed early Friday when a downed Russian rocket struck a residential building in the capital's northern suburbs.

Elsewhere in the north, Ukrainian forces remained in control of the encircled town of Chernigiv, as the Russians try to regroup and rearm.

- The south -

The besieged port city of Mariupol, seen as a key Russian target to link up the annexed Crimea and separatist-controlled Donbas regions, remains encircled and subject to heavy Russian shelling.

Rescue workers have been searching desperately for any survivors buried beneath the rubble of a bombed-out theatre, amid fears that hundreds may be trapped.

Hundreds of thousands of inhabitants are believed to remain in the city, with no running water or heating and food running short.

Russian forces earlier in the campaign took the city of Kherson just north of Crimea, the only major city they have captured so far.

Although Russian forces are trying to push west along Ukraine's Black Sea coast towards Odessa, they have so far failed to encircle the city of Mykolayiv which stands in the way.

The US defense department said while there was continued Russian naval activity in the northern Black Sea off the coast of Odessa, there was no "imminent sign" of an amphibious assault on the city.

- The west and centre -

The west of Ukraine is still well away from the frontline but there have been deadly air strikes by Russia against targets in the region.

Russian missiles struck in the early morning near the airport in the western city of Lviv which has become a hub for refugees as well as diplomats and journalists.

Russian strikes are meanwhile continuing against the central city of Dnipro, seen as a possible point for Russian forces moving from the south and east to join together.

- Casualties -

According to the office for the UN High Commissioner for Human Rights, 780 civilians have been killed in Ukraine, including 58 children.

Moscow has given no toll for casualties among its armed forces in recent days.

Ukraine says over 14,000 Russian soldiers have been killed. Western sources generally give a lower figure but still numbering several thousand.

President Volodymyr Zelensky said last weekend around 1,300 Ukrainian troops had been killed.

- Refugees -

The UN says more than 3.27 million refugees have fled Ukraine since the Russian invasion, with almost two million of them heading to neighbouring Poland.

Millions more are believed to be internally displaced or unable to move.