“Of course, we are concerned about the developments in Russia … But that doesn’t mean we accept that Russia can impose its interests by military means. The annexation of Crimea and Russia’s permanent violation of the ceasefire in Ukraine cannot remain without consequences. I hope every day that Russia will return to co-operation with the West, but until then we are sticking to the sanctions”, Schaeuble said.

Asked what consequences a Russian default could have for Europe, he said only that: “It is up to Moscow to prevent them”.

But the centre-left SPD’s foreign minister, Frank-Walter Steinmeier, speaking in Der Spiegel one day earlier, said a Russian economic collapse is dangerous.

Steinmeier noted the current situation “can’t allow us to go straight back to business as usual”.

But he added: “I'm worried. This is why I oppose any further tightening of the sanctions. Anyone who wants to bring the Russian economy to its knees is completely mistaken if they think that this will bring about greater security in Europe”.

“It cannot be in our interests for this to spiral completely out of control. We should bear this in mind in our sanctions policy”.

Steinmeier said the EU and Nato should hold more talks with Russia to alleviate its trade concerns and to avoid an accidental military confrontation.

“Even during the coldest days of the Cold War, these types of talks [between Nato and Russia military experts] were held. What manoeuvres, movements of troops, and overflights are taking place? We need to talk about such things”, he noted.

He also ruled out the idea of Ukraine joining Nato in the foreseeable future.

“This [Ukraine accession] wasn’t even raised at the last Nato council meeting [in September], let alone debated. Sometimes what is not said at a summit is also important”.

The German comments came ahead of Ukraine-Russia peace talks in Minsk on Christmas eve and an EU foreign ministers’ debate on Russia sanctions on 19 January.

The peace talks broke off without a result, but are expected to resume on Friday.

Meanwhile, the Russian rouble stabilised this week after plunging to record lows against the dollar.

But a leading US ratings agency, Standard & Poor’s, warned on Thursday (25 December) it might downgrade Russian bonds to “junk” in January.

Dmitry Polevoy, the ING Bank’s chief economist on Russia, also told Reuters that “near-term prospects for the rouble remain highly uncertain”.

The currency crisis has seen the price of basic commodities, such as bread, rise steeply this year.

The main cause is a slump in oil prices. But EU sanctions on Russian banks and energy firms are making matters worse by stopping the blacklisted firms from buying debt on international markets.

Three listed banks - Sberbank, Vnesheconombank, and VTB - have challenged the measures in the EU court in Luxembourg on technical grounds.

The EU recently suffered several defeats on sanctions, including on Iran and on the Palestinian militant group Hamas, due to lack of hard evidence.

But cases take two years or more to reach a verdict and no listed company has ever won financial damages from the EU tribunal.