NATO chief Jens Stoltenberg said on Thursday that 'the time has come' for members of the military alliance to consider easing restrictions on Ukraine targeting Russia with weapons supplied from the West.
America had until Thursday stopped short of giving the go-ahead for such military action, even if limited.
British Defence Secretary Grant Shapps has emphasised that UK weapons supplied to Kyiv could be used throughout Ukraine and in Crimea, annexed in a widely-viewed illegal move in 2014 by Russia.
As for whether they could be used to hit targets in Russia, he told the BBC’s Sunday with Laura Kuenssberg earlier this month: “We do not get into how we would allow targeting of our weapons to be used outside of that (the whole of Ukraine), but we do provide our weapons to Ukraine in order for them to defend their country.”
He urged other countries to relax their restrictions on Kyiv for weapons they have supplied.
Western countries appeared increasingly divided in recent weeks on whether or not the Ukrainian military should be allowed to strike targets on Russian soil.
Some of Ukraine's allies argued this is part of legitimate self-defence against an invasion, while others voiced fears it could drag the West into the conflict.
Many of them, including America, Germany and the Netherlands, agreed to allow a limited use of their weapons by Ukraine into Russia to repel attacks on Kharkiv.
Meanwhile, a top Ukrainian commander said Vladimir Putin is building up forces near Ukraine's second biggest city Kharkiv but lacks the troop numbers to stage a major push in the area.
Ukraine says it has stabilised the front in the northeastern Kharkiv region where Russian forces launched a cross-border assault on May 10 that opened a new front in the 27-month-old war and stretched Kyiv's outnumbered troops.
Kharkiv is just 20 miles from the Russian border.
Colonel General Oleksandr Syrskyi said Putin’s army chiefs were continuing to send additional regiments and brigades from other areas and from training grounds to west Russia to bulk up its troops on two main lines of attack in Kharkiv region's north.
That includes the Strilecha-Lyptsi area between two small villages and the vicinity of the border town of Vovchansk where there has been street fighting.
"These forces are currently insufficient for a large-scale offensive and breakthrough of our defence," said Ukrainian Col Gen Syrskyi.
He said Ukraine's "creation of an ammunition reserve" had also reduced the offensive capabilities of Russian forces.
The remark suggested Kyiv's acute shortages of artillery ammunition had eased since the United States finally approved a major aid package in April after months of delay.
US Secretary of State Antony Blinken said on Wednesday that American weapons being delivered were helping to stabilise the Ukrainian front lines.
Russia has concentrated most of its offensive pressure in Ukraine's east where its troops have been able to make slow incremental advances since capturing the town of Avdiivka in Donetsk province in February, but suffering heavy losses.
Putin’s forces launched a series of missiles early on Thursday on Kharkiv, injuring at least four people and damaging infrastructure, local officials said.
Mayor Ihor Terekhov said four people had been injured, a gas pipeline had been damaged and many windows had been broken.
Regional Governor Oleh Syniehubov said eight missiles had been fired at the city, a frequent Russian target in recent weeks.
A community just north of the city had also been hit.
Ukraine's air defence systems destroyed seven Russia-launched missiles and 32 drones overnight, its air force chiefs said on Thursday.
They said Russia had launched a total of 51 missiles and drones.
Russian forces were said to have attacked "military facilities and critical infrastructure in Ukraine".
In another possible developoment, France could soon send military trainers to Ukraine despite the concerns of some allies and criticism by Russia, according to diplomatic sources.
Paris may announce its decision next week during a visit by the Ukrainian president Volodymyr Zelensky, they added.
The diplomats said Paris hoped to forge and lead a coalition of countries offering such assistance to Kyiv's war effort even though some of its European Union partners fear it could make a direct conflict with Russia more likely.
France would initially send a limited number of personnel to assess the modalities of a mission before dispatching several hundred trainers, two of the diplomats said.
Training would centre around demining, keeping equipment operational and technical expertise for warplanes to be provided by the West, they said.
Paris would also finance, arm, and train a Ukrainian motorised brigade.
"The arrangements are very advanced and we could expect something next week," said one of the sources.
Mr Zelensky is due in France on June 6, the 80th anniversary of D-day, when Allied soldiers landed in Normandy to drive out Nazi German forces during World War Two. He will hold talks with French President Emmanuel Macron in Paris the next day.
Ukraine's top commander said on Monday he had signed paperwork allowing French military instructors to visit Ukrainian training centres soon.
Ukraine's Defence Ministry, in a "clarification", said Kyiv had been expressing interest in a project involving receiving foreign instructors since February.
Putin portrayed the possible presence of regular French military in Ukraine as a step towards global conflict.
France has trained about 10,000 Ukrainian troops since Russia invaded Ukraine in February 2022, but has done so within the EU.
The new mission would not be under EU or NATO auspices, the diplomats said.
