Updated: 1:39 p.m. ET
A plot to assassinate Saudi Arabia's ambassador to the United States is a "dangerous escalation" of political violence by the Iranian government, Secretary of State Hillary Clinton said Wednesday as she vowed to hold Iran accountable for its actions.
The alleged plot is a "flagrant violation of international and United States law" and the Obama administration would step up its sanctions in response, Clinton said in remarks at the Center for American Progress.
"This kind of reckless act undermines international norms and the international system," she said. "Iran must be held accountable for its actions... In addition to the steps announced by the Attorney General yesterday, the United States has increased our sanctions on individuals within the Iranian government who are associated with this plot and Iran's support for terrorism."
The Treasury Department said Wednesday it had imposed sanctions against Mahan Air, an Iranian airline that the department has accused of "secretly ferrying operatives, weapons and funds" on behalf of the Islamic Revolutionary Guard Corps.
"Mahan Air's close coordination with the IRGC-QF - secretly ferrying operatives, weapons and funds on its flights - reveals yet another facet of the IRGC's extensive infiltration of Iran's commercial sector to facilitate its support for terrorism," said Under Secretary for Terrorism and Financial Intelligence David S. Cohen in a statement. "Following the revelation about the IRGC-QF's use of the international financial system to fund its murder-for-hire plot, today's action highlights further the undeniable risks of doing business with Iran."
In her remarks, Clinton urged the international community to support the United States in its condemnation of Iran.
"We will work with our international partners to increase Iran's isolation and the pressure on its government," she said. "We call on other nations to join us in condemning this threat to international peace and security."
In a press briefing later on Wednesday, White House Press Secretary Jay Carney said that, in addition to the sanctions, two people had been charged for their involvement in the attempted assassination.
He declined to say whether or not the plot could be tied to Iranian President Mahmoud Ahmadinejad, but noted that "clearly the plotting of this attempted assassination happened at senior levels of the Quds Force," a special unit in Iran's Revolutionary Guard.
He said the administration would be "talking with our partners and international institutions about what transpired here, what a serious thing it is to target an ambassador in a third country, and why we need to take action to ensure that Iran is held accountable."