Top Iranian leaders issued a series of warnings on Tuesday, telling world leaders it is on the brink of restarting a significant portion of its most contested nuclear work, including the enrichment of uranium to prohibited levels that could be used as part of a weapons program.

With tensions mounting between the United States and Iran following a bevy on new sanctions issued by the Trump administration, Iranian leaders warned their counterparts in Europe that the country will begin to enrich uranium—the key component in a nuclear weapon—to levels needed for weapons research.

Iran also will begin to stockpile low-enriched uranium instead of shipping it out of the country, as it had been doing under the nuclear agreement. The Islamic Republic also will stop exporting its heavy water reserves, a nuclear byproduct that can provide a plutonium-based pathway to a weapon.

Both of these moves are enflaming global tension surrounding Iran's nuclear program, which the country has used to receive billions in sanctions relief and cash windfalls as a result of the Obama administration's accord. Iranian leaders insist that if Europe does not reject the new U.S. sanctions and help Tehran bypass them, they will stop adhering the nuclear deal, which several European counties are still party to.

Tehran's demands have become increasingly clear since the Trump administration enacted a hardline policy meant to strangle the ruling regime and its economy. Iran is seeking compensation from Europe—particularly in the arenas hit hardest by U.S. sanctions—in exchange for its adherence to the nuclear pact's prohibitions on uranium enrichment and other matters.

Iran will continue to rollback its adherence to key portions of the deal until all of its "demands are met," according to the country's senior leadership.

"Once our demands are met, we will resume implementation of the ceased undertakings," Iran's Supreme National Security Council said in a recent statement. "Otherwise, the Islamic Republic of Iran will stop compliance with its other undertakings in consequent phases."

"The Islamic Republic of Iran declares that at the current stage, it does not any more see itself committed to respecting the limitations on keeping enriched uranium and heavy water reserves," the statement continued.

Iran has given European countries still party to the deal 60 days to restore Tehran's access to international markets and key banking services. These types of financial facilitators have been off-limits to Iran under the Trump administration's package of sanctions.

Iran also is seeking to have its international oil trade restored.

The Trump administration, after a protracted inter-agency fight, decided last month to stop issuing sanctions waivers to several countries purchasing large amounts of Iranian crude oil. The removal of these waivers effectively killed Iran's oil trade.

Keivan Khosravi, a spokesman for Iran's Supreme National Security Council, said all banking and oil rights must be immediately restored or Tehran will continue with efforts to ramp up prohibited nuclear work.

"As the honorable president declared, concurrent with the SNSC statement, Iran will continue subsequent and staged steps to stop nuclear deal undertakings based on the UNSC statement until the status quo of its oil sales and banking transactions return to the conditions that prevailed before the U.S. withdrawal from the nuclear deal," Khosravi wrote in a memo published Tuesday by Iran's state-controlled press.