(Reuters) - U.S. and EU leaders on Wednesday will pledge to work together on sanctions and on strengthening Europe and Ukraine's energy security as they seek to present a united front to Russia, according to a draft document seen by Reuters.

Throughout the year, the United States has led the push for tougher sanctions, while many governments in Europe, afraid economic measures on Russia will hurt them as much as they hurt Moscow, have been more cautious.

U.S. Secretary of State John Kerry and U.S. Energy Secretary Ernest Moniz are in Brussels for talks with EU leaders.

"The Council (EU-U.S. talks) concurred on the need to coordinate the application of our respective sanctions regimes, while reinforcing measures against separatists as well as in relation to the non-recognition policy related to the illegal annexation of Crimea," a draft statement seen by Reuters said.

The statement said the crisis between Russia and Ukraine that flared up with Moscow's annexation of Crimea in March can be de-escalated as was shown by a tentative October agreement brokered by the EU on gas pricing to try to prevent a supply crisis over the peak winter months.

Moscow cut off Kiev's gas in June in a row over unpaid bills and the price Gazprom charges Ukraine and any truce is very uncertain.

For the future, the draft welcomed "the prospect of U.S. liquefied natural gas exports" to Europe to diversify supplies.

It also said the European Union and the United States stood "shoulder-to-shoulder in their support for Ukraine's new government and underlined the necessity of continuing the reforms in Ukraine's energy sector.”