Zelensky said Ukraine's allies had increased their military support
Zelensky said Ukraine's allies had increased their military support AFP

The United States and Britain have not authorised Ukraine to use long-range missiles on targets inside Russia, fearing an escalation of hostilities, President Volodymyr Zelensky has said, hinting he hoped US leader Joe Biden would change his mind.

Zelensky was speaking late on Friday ahead of a crucial trip to the United States next week, during which he is due to discuss proposals for ending the fighting with Biden, Vice President Kamala Harris and ex-leader Donald Trump.

Kyiv has for weeks been pressing the West to allow it to use Western-supplied long-range weapons to strike targets inside Russia, arguing it could change the course of the war, two and a half years after Moscow's invasion of its neighbour.

"Neither America nor the United Kingdom gave us permission to use these weapons on the territory of Russia, on any targets, at any distance," Zelensky told reporters.

"I think they are worried about an escalation."

Russian President Vladimir Putin has warned that if Ukraine uses long-range weapons supplied to it by the West to strike targets inside Russian territory, that would signify NATO countries were also at war with Russia.

But Zelensky hinted he had not given up hope that Biden -- who has four months left in office -- could make a U-turn in time for a "historic mission" to make "important decisions for Ukraine".

"We have had some decisions in the history of our relationship with Biden -- very interesting and difficult dialogues," the Ukrainian leader said.

"He later changed his point of view."

A close adviser to Biden said this month he would use his remaining time in office to "put Ukraine in the best possible position to prevail".

Zelensky will travel to the United State after a summer of intense fighting.

Moscow's forces have been advancing in eastern Ukraine and Kyiv has held onto swathes of Russia's Kursk region for weeks.

The Russian army is now around 10 kilometres (six miles) away from the eastern Ukrainian hub of Pokrovsk, to where Kyiv has rushed people evacuated from frontline areas.

The war has now dragged on for almost 31 months and efforts to end fighting have so far proved unsuccessful.

Zelensky repeated that Ukraine was "ready" to invite Russia to a second international peace summit in November "because all our allies, including our closest ones" said Russia should be there.

"It is Russia who is fighting Ukraine. There can be no end of the war without one of the parties," he said.

Zelensky said the November summit would be "the foundation for talking in any format with Russia".

Zelensky said he would meet Harris to "see what she thinks about this victory plan" and "definitely" encounter Trump.

Harris and Trump are rival candidates in the knife-edge US presidential election in November.

Zelensky is expected to meet Trump on September 25 or 26. Kyiv is concerned that if he wins a second term Washington could weaken its commitment to Ukraine.

Harris has indicated that she will continue Biden's policies of backing Ukraine, while Trump refused in a recent election debate to take sides over the war.

Trump has been highly critical of the billions of dollars Washington has provided to Kyiv in aid.

Commenting on Friday on a peace plan put forward in spring by China and Brazil, Zelensky dismissed the initiative as too nebulous.

"I don't think it was a concrete plan. I don't see any specific action or stages in it, just generalised procedures," he said.

"Generalisations always hide something."

China and Brazil had promoted the idea of an international peace conference acceptable to both Russia and Ukraine, in which both sides would participate equally and all options would be on the table.

Beijing and Moscow have close ties which have strengthened since the Russian invasion of Ukraine.

Separately, the Ukrainian army announced on Saturday it had struck two ammunition depots in the south and west of Russia overnight, including one near the city of Tikhoretsk in Krasnodar.

The Ukrainian army said the depot was one of Moscow's "three largest ammunition storage bases" and was important logistically for the Russian forces fighting in Ukraine.

The governor of Krasnodar, Veniamin Kondratyev, said 1,200 people were evacuated from a village near Tikhoretsk.

Videos on social media showed a massive explosion that lit up the night sky.

The Ukrainian army said it also struck an arsenal in the village of Oktyabrsky in Russia's Tver region, sparking a fire and an explosion.

Moscow's forces have been advancing towards Pokrovsk in eastern Ukraine since the summer
Moscow's forces have been advancing towards Pokrovsk in eastern Ukraine since the summer AFP
Russia's invasion of Ukraine has dragged on for almost 31 months
Russia's invasion of Ukraine has dragged on for almost 31 months AFP