Live updates: US-Iran war news; Trump says US is ‘low-keying’ negotiations with Iran, as oil price climbs

President Donald Trump said yesterday the US is “low-keying” negotiations with Iran, signaling an emphasis on increasing economic pressure on the country.

Trump is the latest American president to come up against a hardline Iranian regime, with the conflict now in its sixth month.

Here’s a look at how some of Trump’s predecessors interacted with Tehran:

Almost two years after becoming president, Carter faced the Iran hostage crisis after 90 people, including 66 Americans, were taken hostage when the US embassy in Tehran was seized following the Iranian Revolution.

At the beginning of the crisis, Carter sent US officials to Iran to negotiate the release of the hostages, though Iran’s then-Supreme Leader Ayatollah Khomeini refused to meet with them.

Carter’s foreign policy team “often seemed weak and vacillating” during the crisis, according to the US Office of the Historian.

A week later, Carter ordered Iranian assets in US banks to be frozen. In April 1980, when only some of the hostages had been released, Carter cut diplomatic ties with Iran, announcing further sanctions and ordering all Iranian diplomats to leave the US.

The crisis was eventually resolved after US officials, via Algeria, were able to negotiate the release of the hostages.

On January 19, 1981, the US and Iran signed an agreement to release them, and to unfreeze Iranian assets. After more than a year in captivity and minutes after Carter left the presidency, the hostages were released.

Carter’s successor Ronald Reagan declared Iran a “state sponsor of terrorism” in 1984. But in 1986, his administration began covertly looking into ways to improve its relationship with Tehran, despite backing Iraq in the Iran-Iraq war.

Reagan approved a high-profit sale of weapons to Iran despite an embargo, in the hopes that it would yield the return of Americans held hostage in Lebanon by Hezbollah, a militia with close ties to Iran. Funds from some of the arms sales were diverted to the Contras, a minority Nicaraguan political group that was fighting the leftist Sandinista government.

The scandal was called the Iran-Contra affair, and it broke just before the 1986 midterm elections, posing an enormous threat to Reagan and his party.

According to PBS, when the scandal emerged, Reagan publicly denied that any operation had taken place. He then retracted his statement a week later, saying that it had not been an arms-for-hostages deal.

“Despite the fact that Reagan defended the actions by virtue of their good intentions, his honesty was doubted,” PBS explains. “Polls showed that only 14 percent of Americans believed the president when he said he had not traded arms for hostages.”

Obama managed to negotiate a tentative rapprochement with Tehran during his tenure, having vowed to unfreeze US-Iran relations in his 2008 presidential campaign.

Obama spoke by telephone with Iranian President Hassan Rouhani in 2013, the first direct conversation between leaders in Washington and Tehran since 1979, when Carter talked by telephone with Shah Mohammed Reza Pahlavi before Pahlavi was overthrown.

Also in 2013, after years of negotiations, a landmark agreement was reached that slowed Iran’s nuclear development program in exchange for the lifting of some sanctions that caused the country’s economy to stagnate.

The Joint Comprehensive Plan of Action (JCPOA), finalized two years later in 2015, capped Iran’s uranium enrichment for 15 years and facilitated UN-led inspections to ensure Tehran’s adherence to the deal, in exchange for partially dissolving sanctions on Iranian oil wealth and unfreezing billions of dollars in assets.

Trump withdrew from the deal in his first term.