TEHRAN — Iran and Venezuela vowed Saturday to work together to stabilize falling global oil prices as Iran’s supreme leader accused “enemies” of using crude prices as a political weapon.

With President Nicolás Maduro of Venezuela by his side, President Hassan Rouhani of Iran urged members of the Organization of the Petroleum Exporting Countries, or OPEC, to “neutralize schemes by some powers against OPEC and help stabilize an acceptable oil price in 2015.” Mr. Maduro also called for OPEC’s cooperation in stabilizing oil prices.

Both Iran and Venezuela rely on oil prices to drive their respective economies. Oil prices have plunged more than 55 percent since June to less than $50 a barrel, placing a severe strain on the two countries.

Mr. Maduro is touring several OPEC nations to drum up support for a production cut to increase prices. He is to visit Saudi Arabia, the world’s biggest oil exporter, to discuss the oil market slump.