WASHINGTON -- A military strike against Iran's nuclear facilities is "not prudent" at the present moment, America's top military official, Gen. Martin E. Dempsey, told "CNN's Fareed Zakaria GPS" in an interview set to air Sunday morning.

“It’s not prudent at this point to decide to attack Iran,” said Dempsey, the chairman of the Joint Chiefs of Staff, in the interview.

"I think it would be premature to exclusively decide that the time for a military option was upon us," Dempsey added, according to early reports of the interview, noting that he sensed that increased sanctions were beginning to have an effect.

Dempsey's remarks come amid a rising tide of threats and speculation -- some of it media driven -- about the possibility that Israel might launch a military strike against Iran in an attempt to forestall that country's development of a nuclear weapon.

American intelligence assessments say that Iran would have the capability to build a nuclear bomb in the coming years, but it has not yet decided whether to do so.

In recent days, both Israel and Iran appear to have taken a number of steps escalating the tensions, including Iran's recent unveiling of the first domestically produced nuclear fuel rods and its decision over this weekend to move warships into the Mediterranean Sea for only the second time since 1979.

Israelis seem increasingly poised to take military action sooner rather than later, according to both Israeli and American officials, although some have indicated that the Israelis may be willing to let tough sanctions work a bit longer.

In the war of words, American officials have repeatedly signaled that they do not believe military action is in anybody's best interests at this point, something Dempsey and Defense Secretary Leon Panetta sought to drive home in several appearances on Capitol Hill over the last several days, while also trying to tamp down the rhetoric coming from Israel.

Dempsey reinforced this point during his interview on CNN.

“A strike at this time would be destabilizing and wouldn’t achieve their long-term objectives,” Dempsey said about the Israelis, according to Bloomberg. “I wouldn’t suggest, sitting here today, that we’ve persuaded them that our view is the correct view and that they are acting in an ill-advised fashion."

Dempsey also threw cold water on some of the more aggressive plans to intervene militarily in the crisis in Syria, where opposition forces have been carrying out an increasingly bloody revolt against the regime of President Bashar Assad.

"Syria is a very different challenge" from Libya, where American-led NATO forces recently helped end the reign of dictator Muammar Gadhafi, Dempsey added. "It's a different challenge, as you described it, geographically. It's a different challenge in terms of the capability the Syrian military. They are very capable."

Dempsey also called plans to simply arm the opposition "premature."

"I would challenge anyone to clearly identify for me the opposition movement in Syria at this point," Dempsey said, adding that the crisis had grown increasingly complicated over the months.