President Obama spoke to Israeli Prime Minister Benjamin Netanyahu on Thursday amid escalating tensions with Iran.
The White House revealed little about the call, but said it covered "the international community’s efforts to hold Iran accountable for its failures to meet its international obligations.”
The readout said the phone conversation was part of the two leaders' "regular communication and cooperation."
Iran has accused Israel's Mossad of carrying out an assassination. Israeli officials have declined to comment on the accusations. Secretary of State Hillary ClintonHillary Rodham ClintonBiden: ‘Guys, I’m not running’ Trump says email hacking during election 'could've been China' or other groups Maxine Waters: ‘I’ve never seen anybody as disgusting or as disrespectful’ as Trump MORE categorically denied Wednesday that the U.S. had any involvement in the assassination.
The car bombing comes at a particularly sensitive time for the U.S. and Iran.
On Monday, Iran sentenced a former U.S. marine to death for allegedly spying on Iran with the CIA. The State Department said it was "untrue" that the American, Amir Mirzaei Hekmati, was a spy and condemned the death sentence.
Iran also has recently threatened to disrupt a crucial waterway for transporting oil and said it is moving its uranium enrichment to an underground location.
On Thursday, a newspaper in Tehran called for retaliation against Israel, according to The Associated Press. Iran also sent a letter to United Nations Secretary General Ban Ki-moon calling for the U.N. to condemn the assassination, Iran's Press TV said.
The United States and Israel have both said that they will not allow Iran to obtain nuclear weapons and indicated they are willing to use military action. The two countries are staging a large missile defense drill together in the coming weeks.
Tensions between Iran and the West rose last month after the United States and Europe stepped up economic sanctions against Iran in retaliation for its nuclear enrichment program. That prompted Iran to threaten to close the Strait of Hormuz, through which 20 percent of the world’s oil passes. Iran continued its saber rattling by warning U.S. carrier ships to leave the Persian Gulf.
Defense Secretary Leon Panetta has said that Iran would be stopped if it tries to close the strait.