"It could get nasty from here. I think you need to buckle up," the founding partner at energy hedge fund Again Capital said on " Power Lunch ."

President Donald Trump announced Tuesday he will withdraw the United States from the Iran nuclear deal and restore sanctions aimed at severing Iran from the global financial system.

Things could get ugly now that the Trump administration has taken the "hardest possible stand" in terms of rhetoric against Iran, oil expert John Kilduff told CNBC on Tuesday.

U.S. President Donald Trump arrives to announce his decision whether or not to withdraw from the JCPOA Iran nuclear agreement in the Diplomatic Room of the White House in Washington, U.S., May 8, 2018.

Before the announcement, Kilduff had expected Trump would "finesse" and "negotiate" the deal. However, now there is clearly a "U.S.-Israeli-Saudi alliance," which was laid bare after the two countries came out in support of the U.S. decision, Kilduff added.

Oil pared its losses after the news. U.S. West Texas Intermediate crude settled down $1.67, or 2.4 percent, at $69.06 a barrel, well off a 4.38 percent decline earlier in the day. The settlement was delayed by nearly an hour because of extremely high trading volume.

Brent crude fell 46 cents, or 0.6 percent, to $75.71, also paring back an earlier decline of 4 percent.

Kilduff believes we've only started to hear the rhetoric on the issue.

"The temperature now is not going to stay steady or go down, it's only going to go up," he said.

Furthermore, if there is some stepping up of attacks by Iran's proxies on Israel or Saudi Arabia, it could be a breaking point, particularly with Saudi Arabia, Kilduff added.

"One of these next attacks, or potential attacks or attempted attacks ... could be the precursor to something much bigger," he predicted.

While Saudi Arabia still has almost 3 million barrels a day of spare oil capacity, he thinks the kingdom will still let the prices head up toward $85 a barrel.

He said $100 a barrel or more is possible "if there is an outbreak of hostilities."

— CNBC's Tom DiChristopher contributed to this report.