U.S. President Barack Obama said on Thursday that he is keeping a watchful eye on the tension between Israel and Iran, over the country's alleged clandestine nuclear program.

Speaking to ABC News, Obama would not say whether the United States believes the Israelis are preparing a military strike to stop the Islamic Republic’s nuclear program.

“I can’t discuss classified military information, certainly not information that’s shared between countries,” Obama said.

He added, “But you cannot pursue a nuclear weapon. We've imposed the toughest sanctions ever. They had a lot of bite. The Iranian regime is feeling them. And, ultimately, I hope that we can resolve this through diplomatic means. But we're not taking any options off the table.”

The comments are almost a repeat of the remarks Obama made during his State of the Union address earlier this week.

“Look at Iran. Through the power of our diplomacy, a world that was once divided about how to deal with Iran's nuclear program now stands as one,” he said. “The regime is more isolated than ever before; its leaders are faced with crippling sanctions, and as long as they shirk their responsibilities, this pressure will not relent. Let there be no doubt: America is determined to prevent Iran from getting a nuclear weapon, and I will take no options off the table to achieve that goal. But a peaceful resolution of this issue is still possible, and far better, and if Iran changes course and meets its obligations, it can rejoin the community of nations.”

Obama’s comments come after earlier on Thursday, the chairman of the Joint Chiefs of Staff, Gen. Martin Dempsey, said the current U.S.-led push to force Iran to abandon its nuclear ambitions through steadily increasing economic and diplomatic pressure is beginning to show results and it would be “premature” to resort to military force.

In an interview with the American weekly National Journal, Dempsey said that the U.S. remained committed to preventing Iran from acquiring a nuclear weapon, and was prepared to use force if necessary. He cautioned, however, that a conflict with Iran would destabilize the region and potentially have a severe economic impact on the U.S.

“I do think the path we're on—the economic sanctions and the diplomatic pressure—does seem to me to be having an effect,” Dempsey told National Journal. “I just think that it’s premature to be deciding that the economic and diplomatic approach is inadequate.”

Dempsey acknowledged that Israel sees the Iranian threat differently than the U.S. does.

“We have to acknowledge that they ... see that threat differently than we do. It’s existential to them,” he said. “My intervention with them was not to try to persuade them to my thinking or allow them to persuade me to theirs, but rather to acknowledge the complexity and commit to seeking creative solutions, not simple solutions.

The U.S. has grown increasingly concerned that Israel will launch a military strike against Iran without prior warning. Dempsey visited Israel last week and met with high-ranking officials on the issue.