Ukraine on Wednesday accused the United States of helping Russia, saying Washington failed to warn it of incoming missile strikes and slowed the Starlink system it relies on for its battlefield communications and frontline logistics.
US President Donald Trump on Tuesday insisted Washington was still helping Ukraine while a US official told AFP on Wednesday that its policy had "not changed". The EU also said there were "no indications" sharing had stopped.
Ballistic missiles have now struck the Ukrainian capital, Kyiv, for two nights running -- before air raid sirens could sound to warn people to take cover in basements, bomb shelters or metro stations.
Energy facilities were targeted, cutting power to more than 600,000, despite Trump's surprise announcement of an "energy ceasefire" in the nearly five-year conflict.
"Russia has never before shown such ostentatious disrespect toward the United States," said Ukraine's President Volodymyr Zelensky.
"Russia does not consider the American President's statements strong."
Zelensky said on Tuesday night that the lack of notice from Ukraine's Western partners about imminent Russian ballistic-missile launches was "completely unjust".
- Jet-powered drones -
The lack of warning has been reported only rarely over the course of the nearly five-year conflict and Ukrainian officials have suggested the Russian military's use of hard-to-detect missiles or potential technical issues could be to blame.
But one senior Ukrainian official pointed the finger at Washington after slower speeds were reported on Wednesday on some Starlink internet terminals used by its military.
"It's obvious they (the United States) are helping Russia for some reason," the official told AFP, following reports that Washington had threatened to pull intelligence-sharing that Kyiv relies on to detect incoming attacks.
Zelensky adviser Sergiy Beskrestnov linked the attacks and the Starlink restrictions, as the network was "the most effective solution" for protecting Ukraine against fast-moving Russian attack drones.
"Through their actions, our partners are depriving us of one of the few chances we have to defend the country against jet-powered Shahed drones," he wrote on Telegram.
Starlink's owner Elon Musk last weekend backed Trump, who has enraged Western allies by announcing a diesel-supply deal with heavily sanctioned Moscow, and blindsided both sides in the conflict by announcing an "energy ceasefire".
Trump also angrily hit out at Zelensky -- and even suggested he should be replaced as president -- over Ukrainian long-range attacks on Russian energy infrastructure, and urged him to stop.
- Russia 'carefully noting' -
Russia is watching for any sign Washington's backing for Ukraine may have shifted, the Kremlin said.
"We are carefully noting all this. It is too early to draw any systemic conclusions," Kremlin spokesman Dmitry Peskov told reporters.
Five people were killed and dozens more wounded in Kyiv on Wednesday, the authorities said, while significant damage to facilities and equipment knocked out power to swathes of the city.
Power plants also came under ballistic-missile attack in the eastern Kharkiv region, hitting electricity and heating infrastructure, Prime Minister Sergiy Koretsky said.
NATO chief Mark Rutte urged alliance members to step up support for Ukraine's air defences.
"With winter coming and with Russia's aggression unrelenting, allies need to do more, especially in support of air defence," Rutte said.
Zelensky, expected in London on Wednesday for talks with UK Prime Minister Andy Burnham, has said Ukraine is prepared to hold off from striking Russian energy infrastructure.
But he accused the Kremlin of having "squandered the opportunity for de-escalation".
Russia has previously targeted Ukraine's power stations and heating infrastructure, crippling supplies before winter, when temperatures can plummet to as low as -20C.
Ukraine has been pushing its allies for more military support as Kyiv increasingly comes under attack, particularly the supply of advanced interceptor systems to shoot down missiles and jet-powered drones.
Russian ballistic missile attacks were also reported in Zhytomyr in the northwest, and other strikes hit Sumy in the northeast and Chernigiv in the north.
Two people were killed in the central Dnipropetrovsk region and a further person in Zaporizhzhia in the southeast, the authorities said.
The governor of Russia's southwestern Saratov region, citing preliminary estimates, said a Ukrainian drone strike had killed one person in the city of Balakovo.
Moscow mayor Sergey Sobyanin said air defence forces had downed nearly 500 drones flying towards the Russian capital overnight.
Russian authorities said around 160 more were brought down over the Rostov region, while others targeted Moscow.
