US President Donald Trump has once again taken aim at Iran, saying the country is "playing with fire" after Tehran dismissed his warnings over its latest missile test as unfounded and provocative.
In another early morning post on Twitter, Trump said on Friday his administration would not be as "kind" to Iran as the government of his predecessor, Barack Obama.
"Iran is playing with fire - they don't appreciate how 'kind' President Obama was to them. Not me!"
The comment appeared to prompt a quick response from Mohammad Javad Zarif, Iran's foreign minister.
"Iran unmoved by threats as we derive security from our people. Will never initiate war, but we can only rely on our own means of defence," Zarif wrote also on Twitter.
Al Jazeera's Patty Culhane, reporting from Washington, DC, said that the tweets were expected to be followed up by US sanctions against Iran.
"Trump has the support in the US senate to do that. The big question is going to be: 'How will Iran respond?' Do they see that as a violation of the Iran nuclear agreement? That is going to be the key question," she said.
Also on Friday, Iran said it had barred a US wrestling team from participating in the Freestyle World Cup competition in retaliation for an executive order by Trump banning visas for Iranians, Iran's state television reported.
On Thursday, the Trump administration appeared poised to levy fresh sanctions on Iran, in what would mark the first concrete evidence of the new president's tougher stance, hours after he and his national security adviser put Iran "on notice" over missile tests and support for Yemeni rebels.
Asked by a reporter if military action was a possibility, Trump said on Thursday: "Nothing is off the table".
'Baseless, repetitive and provocative'
On Wednesday, National Security Adviser Michael Flynn insisted the missile test was in defiance of UN Security Council Resolution 2231, which calls on Iran not to test missiles capable of delivering a nuclear weapon.
Bahram Ghasemi, Iran's foreign ministry spokesman, on Thursday called the claims "baseless, repetitive and provocative".
Iran has confirmed that it had tested a ballistic missile, but denied that it violated the terms of the nuclear deal.
Tehran said its missiles did not breach UN resolutions because they were for defence purposes only and were not designed to carry nuclear warheads.
Source: News agencies