Terming Iran's "failure" to reach an agreement with International Atomic Energy Agency (IAEA) as "regrettable", the White House has said it was "disappointed" but not surprised by the Tehran's denial of access to the inspectors.
"We regret the failure of Iran to reach an agreement this week with the IAEA that would permit the agency to fully investigate the serious allegations raised in its November report," the White House press secretary, Jay Carney, said on Wednesday at his daily news conference.
The nuclear watchdog on Wednesday acknowledged its "failure" in trying to probe suspicions that Tehran has worked secretly on atomic arms.
The UN nuclear agency, which maintains regular access to both of Iran's enrichment facilities at Qom and Natanz, was seeking additional access in line with Iran's safeguards obligations, to sites and facilities where Iran is suspected of conducting work related to weaponisation activity, he said.
"So, unfortunately, this is another demonstration of Iran's refusal to abide by its international obligations," Carney said.
The United States he said will continue to evaluate, working with its P5-plus-1 partners, the letter that it got from the Iranians for talks.
"But this particular action by Iran suggests that they have not changed their behavior when it comes to abiding by their international obligations," Carney said.
Iran's decision to refuse IAEA inspectors to its facilities, the state department spokesman, Mark Toner, said is not surprising. "It's not particularly surprising. But,...the fact that Iran didn't allow them to visit certain facilities, none of this is surprising. We've seen this before, frankly," he said, adding that the US is awaiting for a more detailed report from the IAEA in this regard before arriving at a definite conclusion.
"We want to see them (Iran) cooperate. We want to see them address the international community's very well-founded concerns about their nuclear program, and that remains our goal. And that remains our goals via the IAEA, but also working within the P-5 plus one," he said.
Toner said the Iranian regime is feeling the squeeze of sanctions and are both trying to shore up domestic support but also, again, feeling the weight of these sanctions that the international community's put on them.
"The two-track approach that we've often talked about is going to remain in place. We want to see negotiations move forward. There is that diplomatic track. But we're not going to ease up on the sanctions," he said.
The United States and its international partners, he said, are working very closely with the IAEA in addressing concerns about Iran's nuclear program, and that cooperation and coordination remains.
"But this is a disappointment. It wasn't all that surprising, frankly. We are going to look at the totality of the issue here and the letter and what we think is the best course of action moving forward," he said.