Updated

Central European nations are now appealing to Capitol Hill leaders to get the United States to increase its natural gas exports should Russia cut off its supply to Ukraine, amid the political turmoil in that country.

Hungary, Poland, Slovakia and the Czech Republic sent a letter Friday to House Speaker John Boehner, R-Ohio. And a similar letter is expected to be sent to Senate Majority Leader Harry Reid, D-Nevada.

Ambassadors from the four countries -- known as the Visegrad Group -- want Congress to support faster approval of natural gas exports, arguing the supply is essential to the region’s economic stability.

“The presence of U.S. natural gas would be much welcome in Central and Eastern Europe,” they told Boehner. “And congressional action to expedite [liquefied natural gas] exports to America’s allies would come at a critically important time for the region."

The concern has grown over the past few months amid the political upheaval in the Ukraine that resulted last month in residents ousting President Viktor Yanukovych and became a major concern several days ago when Russian President Vladimir Putin sent troops into the country’s Crimea region.

"I hope President Obama will heed this call from our allies to use his 'pen and phone' to direct the secretary of Energy to immediately approve pending natural gas export requests and do everything possible to use American energy to reduce the dependency on Russia for our friends in Europe and around the globe," Boehner said in response to the letter.

Ukraine is heavily dependent on Russian natural gas, and previous disputes between Ukraine and Russia have led to gas supply cuts. Russian state gas company Gazprom has increased the pressure on Ukraine's new government, which now owes $1.89 billion for Russian natural gas, by warning that if Ukraine doesn't pay off its debt, there could be a repeat of 2009, when Russia cut off supplies to Europe because of a pricing dispute with Ukraine.

Recent advancements have made it possible for gas that normally flows through Ukraine to the EU to instead flow the other direction, so that nations like Poland and Hungary can supply gas to Ukraine if Russia were to cut off its supply. But with gas supplies limited, the region is still vulnerable unless the U.S. makes it easier to import American natural gas, the ambassadors argued.

Boehner and Republicans have been urging the Obama administration to clear the way for more exports amid a natural gas boom in the U.S.

The Energy Department has only approved six export licenses in recent years out of about two dozen pending.

"The ability to turn the tables and put the Russian leader in check lies right beneath our feet, in the form of vast supplies of natural energy," Boehner wrote this week in an opinion piece in The Wall Street Journal.

The White House has argued that Russia's dependence on gas revenues makes it unlikely that the country will cut off supplies to Europe despite the ongoing crisis in the Ukrainian region of Crimea, where the Russian military has intervened in what the U.S. regards as a violation of international law.

White House spokesman Josh Earnest said Friday that because Europe has had a relatively mild winter, gas supplies are at or above normal levels. He said even if the U.S. did approve more export licenses, it would take until the end of 2015 for gas to be delivered.

"Proposals to try to respond to the situation in Ukraine that are related to our policy on exporting natural gas would not have an immediate effect," Earnest said.

His argument has been supported by industry experts who say only one U.S. company is even far enough along in development to begin thinking about exporting liquefied natural gas.

The Associated Press contributed to this story.