From ABC News:

President Obama appeared in the Diplomatic Reception Room of the White House Thursday afternoon to demand that leaders of the Islamic Republic of Iran take concrete actions to defuse international tensions regarding its nuclear program, beginning with allowing the International Atomic Energy Agency “full access” to Iran’s nuclear facility at Qom within the next two weeks.
IAEA Director General Mohamed ElBaradei, with whom the president has been in close contact, will be arriving in Tehran in the next few days, the president said.
“Our patience is not unlimited,” the president said, alluding to tougher economic sanctions if Iran does not take the necessary steps. “The United States will not continue to negotiate indefinitely, and we are prepared to move towards increased pressure.”
The president said that today’s meeting between Iranian leaders and the representatives of countries from the United Nations Security Council permanent members – the US, China, Russia, France, the UK – as well as Germany, “was a constructive beginning, but it must be followed with constructive action by the Iranian government.”

More here.