A commander of the Revolutionary Guards in Iran issued a statement saying U.S. bases in the region will be in danger if further sanctions on Tehran are imposed.

The Revolutionary Guards are under the direct control of Supreme Leader Ayatollah Khamenei, so the statement can be seen as coming from the top reaches of the Iranian government.

Reuters:

The warning came after the White House said on Friday that President Donald Trump would announce new U.S. responses to Iran's missile tests, support for "terrorism" and cyber operations as part of his new Iran strategy.

"As we've announced in the past, if America's new law for sanctions is passed, this country will have to move their regional bases outside the 2,000 km range of Iran's missiles," Guards' commander Mohammad Ali Jafari said, according to state media.

Jafari also said that additional sanctions would end the chances for future dialogue with the United States, according to state media, and issued a stark warning to American troops.

"If the news is correct about the stupidity of the American government in considering the Revolutionary Guards a terrorist group, then the Revolutionary Guards will consider the American army to be like Islamic State all around the world particularly in the Middle East," Jafari said.

The Revolutionary Guards (IRGC) are Iran's most powerful internal and external security force. The Quds Force, the IRGC's foreign espionage and paramilitary wing, and individuals and entities associated with the IRGC are on the US list of foreign terrorist organizations, but the organization as a whole is not.

The Rev Guards may not be designated as a terrorist group, but that's not relevant.  Diplomatic hair-splitting doesn't matter when the reality is that the Guards' top commanders are all involved in one way or another with funding, training, and supporting terrorists around the region.  The Guard also runs the nuclear and ICBM programs for the government.  Designating the entire organization as a terrorist group is merely a formality.

As for Iranian threats against U.S. bases, they would probably do it if they thought they could survive our response.  But, like North Korea, the Iranians aren't that stupid.  The bluster is for domestic political consumption, not a serious policy suggestion.

At least, we hope that's true.  Also as with North Korea, there is an element of instability and paranoia that makes Iranian actions unpredictable.  It's clear that the Iranians won't stop until someone forces them to or until there is some kind of regime change that alters their behavior.

The latter is preferable to the former, but in the end, what will matter is ending the threat.