President Obama is leveling new sanctions on Iran, targeting the country's oil sector and stepping up efforts to cut off Iran's financial transactions.

"With these actions, we are once again reaffirming our commitment to hold the Iranian government accountable for its actions," the president said in a written statement. "The United States remains committed to a diplomatic solution, but the onus is on Iran to abide by its international obligations."

Obama issued an executive order today to impose new sanctions against the Iranian energy and petrochemical sectors. The action is intended to deter Iran from creating a payment system so that countries may purchase Iranian oil and circumvent existing sanctions. The administration is also taking additional steps to hold responsible institutions that enable financial transactions for Iranian banks.

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The announcement comes on the heels of Mitt Romney's visit to Israel, where he vowed to employ "any and all measures to dissuade the Iranian regime from its nuclear course." The election-year debate over Iran takes place amid growing concern that Israel might take military action to prevent Iran from obtaining a nuclear weapon.

"If the Iranian government continues its defiance, there should be no doubt that the United States and our partners will continue to impose increasing consequences," Obama said.