After Ukrainian forces pushed forward in a lightning advance that has left Moscow's forces in disarray, Russia abandoned military strongholds in northeasternUkraine.

Russia's defence ministry claimed that it had decided to "regroup" and transfer its forces to the south-eastern part of the country.

The Russian retreat is one of the biggest setbacks for Putin since he ordered a full invasion of Ukraine in February.

In his daily video address to the nation, Volodymyr Zelenskyy said that over 2,000 km of territory had been freed.

It is a good idea for the Russian army to run away. Zelenskyy said there will be no place for the occupier in Ukraine.

Zelenskyy promised that the Ukrainian government would guarantee fair treatment for Russian soldiers who surrender.

Videos posted on social media show bedraggled Russian troops who abandoned their vehicles and positions in a hurry. As Ukrainian forces advanced through liberated villages, locals cheered.

The world knows that the Russians can and should be defeated. The defence minister of Ukraine said on Saturday that they were doing that and would do that.

In comments to the Financial Times, Reznikov described the rapid counteroffensive that had taken Russian soldiers by surprise and led them to flee as being like a snowball rolling down the hill.

A snowball rolling down the hill, getting bigger and bigger

Oleksii Reznikov, on the Ukrainian counter-offensive

He said that the counter-offensive was making progress in the south of the country. He said that they were a bit slower in the east than in the west.

The Russian defence ministry made a rare statement on Saturday portraying the withdrawal from Izyum and Balakliia as a move intended to focus attention on a different frontline.

The Russian troops were regrouped to increase their efforts in the direction of the rebels. An operation was conducted over three days to wind down and transfer out Russian troops.

The announcement came after Ukrainian troops captured the north of Izyum, a road and rail hub. Thousands of Russian troops have been cut off from supplies because of this.

There are videos on social media showing Ukrainian troops raising the national flag on the outskirts of Iumzy. It had been liberated according to some officials.

The German foreign minister said the Ukrainian advance was a moment of hope. She spoke on a visit to Kyiv. The time between the UN General Assembly and Christmas is crucial, and we will be there for them.

German Foreign Minister Annalena Baerbock and Ukrainian Foreign Minister Dmytro Kuleba leave a joint news in Kyiv,
German foreign minister Annalena Baerbock and her Ukrainian counterpart Dmytro Kuleba meet in Kyiv on Saturday © REUTERS

After Russian troops were sent south to fend off a separate Ukrainian offensive, analysts said that the Ukrainians took advantage of Russian defences that had been weakened. Lawrence Freedman, professor of war studies at King's College London, estimated that as many as 10,000 Russian troops could be caught in the new maneuver.

Government troops are making significant gains in the region despite stiff Russian resistance, according to a Ukrainian military spokeswoman.

She said that there was an advance of troops along the southern front.

Military analysts said that the Russian military was overwhelmed by the two simultaneous offensives launched by the Ukrainians.

Russian generals are afraid of making mistakes because they want to avoid responsibility. The ability to deal with multidirectional approaches is killed by that.

He said that the armed forces were attacking where Russians didn't expect and in more than one direction.

Government troops were moving towards towns further east.

It was described as a catastrophe by a military commentator embedded with Russian troops.

Below: Counter-offensive on Friday 9 September. Reports on Saturday suggest Ukrainian forces have reached both Kupyansk and Izyum.

Analysts warned against reading too much into the early successes of the Ukranian army, as supply lines could become overwhelmed by the Russians.

The Russians have excellent electronic warfare. They have a lot of good weaponry. They have weapons that are high tech. The former supreme Nato commander said that you always have to respect your opponent.

There are reports of more troops from Russia. Russian positions around Kherson were reinforced by 1,200 Chechen soldiers. The Russian army helicoptered in fresh troops to reinforce Izyum in videos posted on social media on Saturday.