The United States and European Union hit Russia with tough new sanctions Friday in a coordinated riposte to Moscow’s “unacceptable behaviour” in Ukraine despite a fragile truce.

Moscow responded by accusing its foes of seeking to derail the peace push aimed at halting a conflict that has killed more than 2,700 people across Ukraine’s industrial heartland.

Late Friday Russian news agencies reported that Russia’s border officials had waved through the first 35 vehicles in an aid convoy heading for devastated east Ukraine, after Moscow sent in a first convoy in August without Ukraine’s final approval or Red Cross monitors.

While the guns have largely fallen silent after five months of fighting between Ukrainian forces and pro-Russian rebels, the rhetoric in the worst East-West crisis since the Cold War has just grown louder.

In some of the toughest measures yet to punish the Kremlin for allegedly fomenting the insurgency, Washington targeted Russia’s top bank Sberbank — which holds the deposits of nearly half all Russian savers — and leading energy and technology companies.

“These steps underscore the continued resolve of the international community against Russia’s aggression,” said US Treasury Secretary Jacob Lew.

The fresh EU measures were also aimed at major Russian energy, finance and defence companies, including oil giant Rosneft and famed weapons manufacturer Kalashnikov.

The 28-member bloc also imposed asset freezes and visa bans on a host of Russian figures, including allies of President Vladimir Putin, as well as rebels in Ukraine and Crimea, a Ukrainian region that Russia annexed.

The ruble sank to a historic low and Moscow stock markets fell, fearful of the impact on an economy already teetering on the brink of recession.

However, in what was seen as a concession, Brussels agreed to delay implementing a trade deal with Ukraine that is deeply opposed by Russia.

A dismissive Putin said the sanctions would have little effect and accused the West of using them as an “instrument to destabilise international relations”.

EU nations finally approved the measures after deep divisions emerged in the wake of the ceasefire, with some worried about the effect on their own economies of any reprisals by Moscow.

Brussels will reconsider the measures after reviewing the truce at the end of September.

Moscow has already threatened to bar EU airlines from its airspace, and has drawn up a list targeting imports of consumer goods and second-hand cars from the West.