The White House on Tuesday strongly condemned the raid on the British embassy in Tehran in which six diplomats were briefly taken hostage.
The assault -- which hard-line student protesters said was a reaction to sanctions imposed on Iran by Britain -- resulted in smashed windows, hurled petrol bombs and burning of the British flag.
"The United States condemns in the strongest terms the storming of the British Embassy in Tehran," White House Press Secretary Jay Carney said in a statement. "Iran has a responsibility to protect the diplomatic missions present in its country and the personnel stationed at them. We urge Iran to fully respect its international obligations, to condemn the incident, to prosecute the offenders and to ensure that no further such incidents take place either at the British Embassy or any other mission in Iran."
Carney said the U.S. State Department is in contact with the British government and has offered whatever support it needs.
The European Union also chastised the demonstrators' actions.
"We strongly condemn this totally unacceptable incursion and call on the government of the Islamic Republic of Iran immediately to fulfill its international obligations... to protect diplomats and embassies," said Maja Kocijancic, a spokeswoman for EU foreign policy chief Catherine Ashton, told Reuters.
Earlier this month, the U.S. government announced additional sanctions on Iran after the U.N.'s nuclear watchdog reported that Tehran was attempting to revive its nuclear weapons program after claims it was defunct.
Actions in Iran have also been hard to gauge and follow. A reported blast in Isfahan, Iran, led to a new investigation by the U.S. intelligence community. Satellite imagery was being used to assess conditions on the ground, an official told Fox News, particularly since Isfahan is home to a known uranium conversion facility, believed to be six to 0 miles out of town.
The official said "several explanations" could account for the blast since Isfahan is also a large center for the oil and gas industry. Given the explosion earlier this month at a missile base in the west of Tehran, the official said the question is whether a campaign against Iran's nuclear program is already under way.
Previewing Vice President Biden's trip to Europe, Tony Blinkin, Biden's national security adviser, said Iran's making threatening statements "doesn't serve anyone's purpose, least of all the Iranians."
He added that reaction to the International Atomic Energy Agency report and the Iranian assassination plot against the Saudi ambassador to Washington has given the world community deep pause over Iran's recent behavior.
"The fact of the matter is that the world is deeply concerned with Iran's activities in a number of areas starting with their nuclear program," he said.
On Monday, President Obama said the European Union and the U.S. were working together on a security cooperation that will "continue to place pressure on the Iranian regime to stand down when it comes to the development of nuclear weapons."
Meeting with the European Council president and European Commission president at the White House, Obama said he hoped diplomatic resolutions would allow Iran to "use peaceful nuclear energy in a way that's consistent with their international obligation."
Former Sen. Evan Bayh, D-Ind., told Fox News that storming the embassy "is crossing a bright red line that is totally impermissible."
Bayh said the incident was a byproduct of Iran trying to deflect anger from its populace outwards rather than on the leaders who have created domestic turmoil through policies that have resulted in sanctions that are working to damage the economy.
"Unemployment is high, inflation is high, the Iranian people are unhappy," said Bayh, a Fox News contributor. "It's a time-honored practice of dictatorial government to try to redirect that unhappiness outward toward others, including in this case, the U.S., Great Britain and the West in general."