Russia should be finished calling up reservists in two weeks, President Vladimir Putin said on Friday, promising an end to a divisive mobilisation that has seen hundreds of thousands of men summoned to fight in Ukraine and huge numbers flee the country.

Putin also said Russia had no plans "for now" for more massive air strikes like those it carried out this week, in which it fired more than 100 long range missiles at targets across Ukraine.

Putin ordered the mobilisation three weeks ago, part of a response to Russian battlefield defeats. He has also proclaimed the annexation of four partially occupied Ukrainian provinces and threatened to use nuclear weapons.

Russia has since seen the first signs of public criticism of the authorities since the war began and officials have acknowledged some mistakes. Members of ethnic minorities and rural residents have complained of being drafted at higher rates than ethnic Russians and city dwellers.

Defending the order, Putin said the front line was too long to defend solely with contract soldiers.

He said 222,000 out of an expected 300,000 reservists had already been mobilized. "This work is coming to an end," he told a news conference at the end of a summit in Kazakhstan. "I think that in about two weeks all the mobilisation activities will be finished."

Since the mobilisation order was given, Russian forces have continued to lose ground in eastern Ukraine and the south.

Ukrainian President Volodymyr Zelenskiy, in his nightly video address, once again said Ukraine's forces would retake all of its territory.

"Yes, they still have people to throw on the battlefield, they have weapons, missiles, they have (Iranian-made) Shaheds which they use against Ukraine," he said. "They still have the possibility to terrorise our cities and all Europeans, blackmailing the world. But they have no chance of succeeding and will have none because Ukraine is moving forward."

Zelenskiy also said he had spoken to Saudi Arabian Crown Prince Mohammed bin Salman. "We discussed possibilities for acting together in the interests of our countries and our peoples. I believe that the results we need are possible," he said, giving no details.

The US government accused the Saudis of kowtowing to Russia - as it wages the war in Ukraine - when the OPEC+ oil producer group it leads announced this month it would cut its oil production target.

New troops take casualties

A Western official said some of the newly mobilised Russian troops were already on the battlefield taking casualties, and that their presence was unlikely to turn the tide. "It is clear that they have been fielded with very, very limited training and very, very poor equipment," the official said.

The official also suggested Russia had too few missiles to sustain attacks like those this week: "Russia is rapidly exhausting its supply of long-range precision munitions, in particular its air-launched cruise missiles."

Ukraine's top general, Valeriy Zaluzhnyi, struck an upbeat tone after his country's rapid advances in the northeast and south.

"The strategic initiative is in our hands, so the main thing is not to stop," Zaluzhnyi said after speaking by phone with the commander in chief of Europe's combined NATO forces, US General Christopher Cavoli.

Ukraine's General Staff said on Facebook late on Friday that Ukraine's forces had destroyed large amounts of Russian arms and equipment in Antratsyt south of Luhansk, where Ukraine hopes to recapture major towns after its successes in Kharkiv region.

It said Russian forces had launched more artillery and air strikes on towns including Konstantynivka southwest of Bakhmut, their main target in Donetsk region, and Zaporizhzhia city.

Reuters was not able to verify the battlefield reports.

Separately, Belarusian President Alexander Lukashenko put his country on what he called a heightened state of terrorism alert on Friday, the latest gesture hinting at growing pressure to join the war.

Lukashenko, Putin's closest international ally, has allowed Russian forces to use Belarus as a staging ground but so far kept his own troops out. This week he announced Russian troops would be joining Belarusian forces near the Ukrainian border.

- Reuters