Live updates: follow the latest news on Russia-Ukraine
A Russian-backed breakaway region of Moldova is fast becoming the new front in the war as Russia steps up its offensive in the southern Ukraine.
The Kremlin is accused of staging "false-flag attacks" in Transnistria, a region in Moldova which it occupies.
The interior ministry of Transnistria said on Wednesday that shots were fired at a village housing a Russian arms depot after drones flew over from Ukraine.
"Last night, several drones were noticed in the sky over the village of Kolbasna," the Transnistrian interior ministry said on its website. "The drones were launched on to the territory of Transnistria from Ukraine."
The developments came as Russia intensified attacks on the Black Sea port city of Odesa, which lies less than 160 kilometres east of Transnistria.
A vital bridge in the Odesa region was hit by missiles on Wednesday, a day after several blasts shook Transnistria.
The bridge near the town of Zatoka, 60 kilometres south of Odesa, was damaged in the attack, said Oleksandr Kamyshin, chief executive of Ukraine’s railway operator.
“Today, at 06.45am, the bridge over the Bilhorod-Dnistrovskyi estuary in Odesa region was again hit with missile strikes,” Mr Kamyshin wrote on the Telegram messaging app. There were no reported casualties among railway workers, he said.
Lesia Vasylenko, a Ukrainian MP, said the destruction of the bridge cut off three districts and passage to the border with Romania.
The same bridge was hit by a missile on Tuesday. The dramatic moment was captured on video and posted online. A huge cloud of smoke can be seen rising in the distance after a loud explosion was heard.
Moldovan officials arranged an emergency meeting on Tuesday, with security forces put on high alert after a series of blasts that destroyed radio antennae.
The explosions stoked fears of a potential spillover from the war in neighbouring Ukraine.
The Institute for the Study of War, a US think tank, said Moscow had used the region to stage “false-flag attacks”.
The region is internationally recognised as part of Moldova but is occupied by Russian forces.
The ISW said Russian battalions stationed in Transnistria were probably “not sufficient” to stage an attack on Odesa by themselves. However, experts noted that troops in the region could support Russian forces in attacking the Ukrainian city.
“Russia is staging false-flag attacks in Transnistria, Moldova ... setting conditions for further actions on that front,” the ISW said.
“The two motorised rifle battalions Russia has illegally maintained in Transnistria since the end of the Cold War are not likely sufficient to mount a credible attack on Odesa by themselves, nor are the Russians likely to be able to reinforce them enough to allow them to do so. They could support more limited attacks to the north-west of Odesa, possibly causing panic and creating psychological effects to benefit Russian operations in the south of Ukraine.”
Tension between the Kremlin and the West was exacerbated on Wednesday with Russia’s announcement that it would cut gas supplies to Nato and EU members Poland and Bulgaria.
Gazprom, the state-owned energy producer, said it would cease deliveries to the two countries because they had refused to pay in Russian roubles, as President Vladimir Putin had demanded.
European gas prices shot up, prompting EU Commission President Ursula von der Leyen to accuse the Kremlin of blackmail.
The move came a day after the US and western allies vowed to speed up and improve military supplies to Kyiv.
Polish Prime Minister Mateusz Morawiecki told the parliament in Warsaw that the country would not be cowed by the gas cut-off.