Analysts say that the growing tensions between Russia, Ukraine and other countries have cast doubt over European energy markets and could lead to prolonged periods of high prices.

CNBC spoke to Dan Yergin on Monday, a energy expert who said that it was a tight market for gas.

If the crisis escalates, gas prices in Europe – which soared to highs last year – could surge further, warned research firm Capital Economics in a note over the weekend.

Capital Economics chief emerging markets economist William Jackson stated that Europe relies on Russia to get its natural gas. Stock supplies are very low at the moment.

He stated that if sanctions were placed on Russia’s exports of energy or if Russia used gas exports to leverage its position, European natural gas prices could soar.”

Tensions between Russia and Ukraine have ratcheted upMultiple reports have claimed that Russian troops are present at Ukraine’s border in the last few months.

The development prompted speculation that Russia is preparing to invade the country and set off fears of a repeat of Moscow’s illegal annexation and occupation of Crimea in 2014. These allegations have been repeatedly refuted by Moscow.

The talks aimed to ease the crisis came to an abrupt halt last week.

U.S. representatives and NATO members emerged from several days of high-stakes discussions with top Russian officials with no resolution – but with warnings that the situation along the Ukraine border is in fact getting worse.

There is talk of a crisis in the near future the U.S. could impose sanctions on RussiaTo stop the Kremlin invading Ukraine.

Capital Economics says that if it happens European gas prices may surpass the 180 pounds/MWh peak seen last year.

Jackson stated that “some states, especially those in Eastern Europe, which are extremely dependent on Russian gaz, may be forced to ration their power.”

The third quarter of last year saw a huge gas shortage in Europe. European power prices spiraling to multi-year highs.

Jefferies stated in a note Sunday that Russia’s gas supply was already less than it used to be.

According to U.S. investment banks, imports from Russia of natural gas into Northwestern Europe decreased by 38% in the period August through December compared with the 2018 period.

Gas stockpiles in Europe are also lower than average – and are down by 21% as of Jan. 12, versus the five-year average, the firm said.

We expect that the high prices for natural gas will continue. Jefferies stated that gas flows from Russia would remain low in the coming 2021/22 heating seasons with record-low stockpiles.

“There was a tendency to think that this crisis is a one-off when it began last year,” Yergin explained, referring to Europe’s gas shortage of 2021. This could be a recurring problem if one looks at investment levels and demand trends.