By Barbara Starr

President Barack Obama talked with Israeli Prime Minister Benjamin Netanyahu in a call Tuesday night about the threat posed by Iran's nuclear program, according to a White House statement.

Obama placed the call to Netanyahu, a senior administration official told CNN.

The one-paragraph statement from the White House, which referred to the Obama-Netanyahu discussion as "a part of their ongoing consultations," followed reports earlier in the day that the White House had rejected a request by Netanyahu to meet with Obama this month to discuss Iran's nuclear program.

CNN's Wolf Blitzer, citing Israeli sources, reported that the Israelis were told Obama's schedule would not permit a meeting even though Israel offered to have Netanyahu travel to Washington.

Obama and Netanyahu are both due to address the United Nations in New York in late September but not at the same time.

The Obama administration pushed back later Tuesday.

"Contrary to reports in the press, there was never a request for Prime Minister Netanyahu to meet with President Obama in Washington, nor was a request for a meeting ever denied," the White House said Tuesday night in its statement, which made reference to "our close cooperation on Iran and other security issues."

Netanyahu has shown growing impatience with what he says is a lack of clarity by the Obama administration on articulating so-called "red lines" that Iran cannot cross if it wants to avoid war over its nuclear ambitions.

The administration has resisted pressure to take that step.

U.S. intelligence officials have said they do not believe Iran has decided to develop a nuclear weapon, even as evidence continues to mount that they are improving their ability to do so. Iran said its intentions are peaceful.

Atomic enrichment in and of itself is not the red line, a U.S. official told CNN.

But Israel feels a sense of urgency with negotiations aimed at curbing Iran's nuclear ambitions failing to produce an agreement and sanctions falling short of their intended effect.

Concerns in Washington that Israel could launch a pre-emptive strike on Iran's nuclear facilities prompted a wave of visits this summer to Israel by several top Obama administration officials.

Defense Secretary Leon Panetta said that he is confident the United States is capable of monitoring Iran and can strike militarily, if necessary.

"We have pretty good intelligence on them, we keep a close track on them," Panetta told CBS' "This Morning" in an interview aired on Tuesday.

"We think we've got the ability to be able to strike at them effectively if we have to ... whenever we have to, we have the forces in place," he said.

The U.S. official, who spoke anonymously in order to freely discuss the sensitive issue, said Panetta is "frustrated" by the partial impact of sanctions, saying he has not seen "the kind of response" that would have been expected from the Iranian regime, given that the sanctions have been tightened.

The United States has sanctioned Iranian banks, companies and individuals as part of an effort by western powers to pressure the Tehran government.

Netanyahu also said sanctions were only having a partial impact.

"The sanctions have hurt the Iranian economy, but they haven't stopped the Iranian nuclear program. That's a fact," Netanyahu said on Tuesday at a news conference in Jerusalem.

CNN's Dan Lothian, Barbara Starr and Lesa Jansen contributed to this report.