The team was dispatched after emergency talks in Brussels between the commission and Russian and Ukrainian fuel company executives to help resolve a price dispute between their countries that has severely disrupted natural gas deliveries.

Some 20 countries have been affected, especially in the Balkan region, where the crisis has left tens of thousands of households in the cold and forced schools, hospitals and factories to close.

Both the commission and the Czech presidency of the EU declared the situation  unacceptable and demanded that Russia and Ukraine restore gas supplies immediately.

The monitors will be checking the flow to ensure that Russia and Ukraine honour contracts to pump gas to Europe. The crisis began at the start of the year, when the two countries broke off talks over how much Ukraine should pay for Russian gas. A few days later, the gas stopped flowing.

This is not the first time tensions between Ukraine and Russia have squeezed EU gas supplies. Similar disputes in recent years have shown the need to reduce the EU’s reliance on foreign energy, one of the commission’s top priorities.

The EU gets about a quarter of its natural gas from Russia, mostly through pipelines in Ukraine. The dependence varies widely though, with some countries relying on Russia for nearly all their gas.

Moscow agreed to the monitors after talks with Czech Prime Minister Mirek Topolánek and German and Russian leaders. A special Energy Council will take place on 12 January to look at the situation, including monitoring. The Czech Republic took over the rotating EU presidency on 1 Jan., just as the crisis began.