Oren Dorell

USA TODAY

Sanctions imposed on Iran Friday mark a more aggressive approach by the Trump administration to counter Tehran's ballistic missile development and support for militant groups across the Middle East.

But the sanctions don't impact the Iran nuclear deal, according to the administration.

Here are answers to key questions about the sanctions:

Why now?

The new sanctions, which target individuals and entities involved in Iran’s missile program and support combatant militants outside of Iran, were triggered by Iran’s missile test on Sunday.

The sanctions are initial steps to retaliate for provocative actions that violate regional norms, a senior administration official told reporters on a conference call. The official was not authorized to speak publicly on the subject. The official said Iran faces a choice on how to proceed because the Trump administration will continue to pressure it to change its behavior.

Trump sanctions Iranian companies, individuals tied to missiles

Is the Iran nuclear deal affected?

Three senior administration officials on the call were emphatic that the new sanctions did not conflict with the nuclear deal negotiated by the United States, five other world powers and Iran to limit that country’s nuclear program to peaceful activity in return for the lifting of international sanctions.

Iran said a nuclear agreement did not cover its missile activity, that a United Nations Security Council resolution that approved the deal only bars launches of missiles capable of carrying nuclear warheads, and this missile test involved a conventional weapon.

That was disputed by a second administration official, who also requested anonymity, and said the missile could carry a nuclear weapon.

Rep. Eliot Engel, the ranking Democrat on the House Foreign Affairs Committe, praised Trump's approach.

"With the nuclear agreement in place, the United States and our allies need to push back against Iran’s destabilizing behavior around the world," Engel said in a statement.

The new sanctions can be imposed without impacting previous sanctions lifted by Europe under the nuclear deal, said Mark Dubowitz, executive director of the Foundation for the Defense of Democracies, a think tank in Washington.

"Our European allies have always understood that the (nuclear deal) does not preclude the sanctioning of entities involved in malign activities outside the nuclear program," Dubowitz said.

"That was a position of the Obama administration," which negotiated the Iran deal, he said.

Iran says new U.S. sanctions are a violation of the nuclear deal.

What other sanctions can the U.S. impose?

They could target sectors of Iran’s economy that support its missile program, and foreign companies that supply the missile program, said Dubowitz, a sanctions expert who has advised Congress and both the Obama and Trump administrations on sanctions.

Those segments include Iran's mining, metallurgy, petrochemicals, construction, telecommunications, computer science and electronics industries, he said.

Many of these industries are controlled by Iran's Islamic Revolutionary Guard Corps (IRGC), which could be severely hampered by new sanctions, Dubowitz said.

"Now is not the time for companies to expand business with the Iranian regime,” said Rep. Peter Roskam, R-Ill., who on Wednesday co-sponsored a bill that would impose new non-nuclear sanctions on Iran.

Could sanctions lead to war?

Dubowitz said setting clear expectations and harsh consequences for Iran has historically helped to curb Iran's expansionary impulses and avoid further conflict.

Iran only sued for peace in the Iran-Iraq war when it thought in 1988 the U.S. was going to intervene on Iraq's behalf after the U.S. mistakenly shot down an Iranian airline, he said. Iran only froze its nuclear program and agreed to negotiate nuclear limits with the Europeans in 2003, after the U.S. invaded Iraq and deposed Iraqi dictator Saddam Hussein, while then-president George W. Bush listed Iran in an "Axis of Evil."

Iran expanded its support for terrorists and its missile activity under the "permissive environment under Obama," Dubowitz said. "The Iranians will push forward until they feel steel."

What else is Iran doing in the region?

Iran supports militias in Yemen, Iraq, Syria, Lebanon and the Gaza Strip, many consider terrorists by the U.S. government. Iran-backed Houthi rebels in Yemen last weekend attacked a Saudi warship, killing two sailors.

Iran has provided military support to Syrian President Bashar Assad in a six-year civil war that has cost an estimated 500,000 deaths, according to the United Nations. Iran also supports the Lebanese militia and political party Hezbollah, which has built an arsenal of thousands of Iranian missiles aimed at U.S.-ally Israel. Iran also trains and arms Iraqi militias that are fighting the Islamic State, an enemy it has in common with the United States.

Iran defends these actions as its right to be involved in political upheaval near its borders. If anyone is guilty of meddling in the region it is the U.S., the Iranian government says.