WASHINGTON/DUBAI (Reuters) - Iran and the United States sent mixed signals on Tuesday about resolving their disputes as Iran’s supreme leader threatened to further breach the 2015 nuclear deal while the U.S. president cited “a lot of progress.”

FILE PHOTO: Iran's national flags are seen on a square in Tehran February 10, 2012, a day before the anniversary of the Islamic Revolution. REUTERS/Morteza Nikoubazl/File Photo

Tensions have risen since U.S. President Donald Trump last year abandoned the major powers’ nuclear deal with Iran under which Tehran agreed to curtail its nuclear program in return for the lifting of global sanctions crippling its economy.

Washington has since reimposed draconian sanctions to throttle Iran’s oil trade in a “maximum pressure” policy to force Tehran to agree stricter limits on its nuclear capacity, curb its ballistic missile program and end support for proxy forces in a regional power struggle with U.S.-backed Gulf Arabs.

Fears of direct U.S.-Iranian conflict have risen since May with several attacks on oil tankers in the Gulf, Iran’s downing of a U.S. surveillance drone, and a plan for U.S. air strikes on Iran last month that Trump called off at the last minute.

Iran’s supreme leader on Tuesday said Tehran would keep removing restraints on its nuclear activity in the deal - struck with Britain, China, France, Germany Russia and the United States - and retaliate for the seizure of an Iranian oil tanker.

Ayatollah Ali Khamenei, Iran’s ultimate authority, accused Britain, Germany and France of failing to uphold obligations under the deal to restore Iranian access to global trade, especially for Tehran’s oil exports blocked by U.S. sanctions.

“According to our foreign minister, Europe made 11 commitments, none of which they abided by. We abided by our commitments and even beyond them. Now that we’ve begun to reduce our commitments, they oppose it. How insolent! You didn’t abide by your commitments!” Khamenei said, according to his website.

“We have started to reduce our commitments and this trend shall continue,” Khamenei said in remarks carried by state television.

United Nations nuclear inspectors last week confirmed Iran is now enriching uranium to 4.5% fissile purity, above the 3.67% limit set by its deal, the second breach in as many weeks after Tehran exceeded limits on its stock of low-enriched uranium.

The level at which Iran is now refining uranium is still well below the 20% purity of enrichment Iran reached before the deal, and the 90% needed to yield bomb-grade nuclear fuel. Low-enriched uranium provides fuel for civilian power plants.

Commitments under threat: tmsnrt.rs/2XSTTiN

IMPASSE

Khamenei has previously upbraided European powers for not standing up to Trump and circumventing his sanctions noose.

But it was the first time Khamenei explicitly pledged to press ahead with breaches of the nuclear deal, spurning European appeals to Iran to restore limits on enrichment aimed at obviating any dash to development of atomic bombs.

“So far, efforts to win gestures from Iran to de-escalate the crisis are not succeeding (as) Tehran is demanding the lifting of sanctions on its oil and banking sectors first,” a European diplomatic source told Reuters.

Iran denies any intent to acquire nuclear weapons, and has said all its breaches could be reversed if Washington returned to the deal and its economic dividends were realized. Tehran has accused Washington of waging “economic war.”

“Western governments’ major vice is their arrogance,” Khamenei said. “If the country opposing them is a weak one, their arrogance works. But if it’s a country that knows and stands up against them, they will be defeated.”

Separately, Iran denied it was willing to negotiate over its ballistic missile program, contradicting U.S. Secretary of State Mike Pompeo and appearing to undercut Trump’s statement that Washington had made progress on its disputes with Tehran.

The chief U.S. diplomat said Iran had signaled it was ready to negotiate about its ballistic missiles during a White House Cabinet meeting at which Trump said: “We’ll see what happens. But a lot of progress has been made.”

Pompeo appeared to be reacting to a comment by Iran’s foreign minister that Tehran would discuss its missile program after Washington stopped arming allies the United Arab Emirates and Saudi Arabia, something the United States is unlikely to do.

His assessment drew a quick denial from the spokesman for Iran’s mission to the U.N., who posted on Twitter: “Iran’s missiles ... are absolutely and under no condition negotiable with anyone or any country, period.”

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Speaking during the U.S. Cabinet meeting, Trump struck a conciliatory note, saying Washington wanted to help Tehran.

“We’ll be good to them, we’ll work with them. We’ll help them in any way we can, but they can’t have a nuclear weapon. We’re not looking, by the way, for regime change,” Trump said. “They (also) can’t be testing ballistic missiles.”

BRITAIN’S ‘PIRACY’

Pompeo told the meeting Iran had “for the first time” signaled it was prepared to negotiate about its ballistic missiles, suggesting this was the result of U.S. economic pressure.

He appeared to be referring to comments by Iran’s foreign minister on Monday in which he said Shi’ite Iran would discuss its missile program only after the United States ceased arming its regional Sunni rivals Saudi Arabia and the UAE.

Iranian Foreign Minister Mohammad Javad Zarif told NBC’s “Nightly News with Lester Holt” program that once the Trump administration removed sanctions it has restored since leaving the nuclear deal the “room for negotiation is wide open.”

Asked if that could include its ballistic missile program, Zarif replied: “If they want to talk about our missiles, they need, first, to stop selling all these weapons, including missiles, to our region.”

The Islamic Republic has repeatedly ruled out negotiating under sanctions duress from Washington. It has long said its ballistic missile program is defensive and non-negotiable.

On Monday, European parties to the nuclear deal decided not to trigger its dispute mechanism over Iran’s breaches in favor of pursuing more troubleshooting diplomacy.

In his comments, Khamenei also said Iran would respond to Britain’s “piracy” over the seizure in early July of an Iranian oil tanker in Gibraltar.

“Evil Britain commits piracy and steals our ship ... and gives it a legal appearance. The Islamic Republic...will not leave this wickedness unanswered and will respond to it at an appropriate time and place,” Khamenei said.

Following his remarks, a spokesman for British Prime Minister Theresa May said an escalation of tensions between Western states and Iran was in no one’s interest.

Iran has called on Britain to immediately release its oil tanker, which was detained by British Royal Marines on the suspicion that it was breaking European sanctions by taking oil to Tehran’s close ally Syria.