Iranian officials warned that Tehran would decisively respond to any U.S. attacks, as President Biden vowed unspecified action following the deaths of three American soldiers in Jordan.

‘We hear threats coming from American officials, we tell them that they have already tested us, and we now know one another, no threat will be left unanswered,’ Iranian Revolutionary Guards’ chief Hossein Salami said on Wednesday, Reuters reported, citing the semi-official Tasnim news agency.

‘We are not after war, but we have no fear of war,’ Salami, who answers only to Supreme Leader Ayatollah Ali Khamenei, said at an event Wednesday, according to the state-run IRNA news agency. 

Another warning came from Amir Saeid Iravani, Iran’s ambassador to the United Nations in New York. 

‘The Islamic Republic would decisively respond to any attack on the country, its interests and nationals under any pretexts,’ Iravani said, according to the IRNA. He described any possible Iranian retaliation as a ‘strong response,’ without elaborating. He gave a briefing to Iranian journalists late Tuesday, according to IRNA. 

Iravani also denied that Iran and the U.S. had exchanged any messages over the last few days, either through intermediaries or directly. The pan-Arab satellite channel Al Jazeera, which is based in and funded by Qatar, reported earlier that such communication had taken place. Qatar often serves as an intermediary between Washington and Tehran.

Such messages have not been exchanged,’ Iravani said.

On Saturday, a general in charge of Iran’s air defenses described them as being at their ‘highest defensive readiness.’ That raises concerns for commercial aviation traveling through and over Iran as well. After a 2020 U.S. drone strike in Baghdad killed Qassem Soleimani, the commander of the elite Quds Force of Iran’s Revolutionary Guards, Iranian air defenses mistakenly shot down a Ukrainian passenger plane, killing all 176 people on board. 

In response to the 2020 U.S. strike, Iranian Revolutionary Guards also targeted the Ain al-Asad U.S. base in Iraq.

Speaking to reporters as he left the White House on a campaign trip to Florida Tuesday, Biden vowed to reporters he decided how to respond after three U.S. service members were killed and more than 40 others were injured in a drone strike by Iranian-backed militants on a post in Jordan near the Syrian border crucial to the anti-ISIS mission in the region. 

The president did not elaborate. Meanwhile, attacks by the Iranian-backed Houthi rebels continue in the Red Sea, most recently targeting a U.S. warship. The missile launched Tuesday night targeted the USS Gravely, an Arleigh Burke-class guided missile destroyer, the U.S. military’s Central Command said in a statement.

‘There were no injuries or damage reported,’ the statement said.

A Houthi military spokesman, Brig. Gen. Yahya Saree, claimed the attack in a statement Wednesday morning, calling it ‘a victory for the oppression of the Palestinian people and a response to the American-British aggression against our country.’ Saree claimed the Houthis fired ‘several’ missiles, something not acknowledged by the U.S. Navy. Houthi claims have been exaggerated in the past, and their missiles sometimes crash on land and fail to reach their targets. 

The Houthis claimed without evidence on Monday to have targeted the USS Lewis B. Puller, a floating landing base used by the Navy SEALs and others. The U.S. said there had been no attack. Since November, the rebels have repeatedly targeted ships in the Red Sea over Israel’s offensive against Hamas in Gaza. But they have frequently targeted vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for global trade between Asia, the Mideast and Europe.

The Houthis hit a commercial vessel with a missile on Friday, sparking a fire that burned for hours.

Five members of the Iranian Revolutionary Guards have been killed following Israeli strikes in Syria since late December, according to Reuters. 

The Tasnim news agency reported Monday that another Israeli strike hit an ‘Iranian military advisory center’ in Syria, killing two. Iran’s envoy to Syria denied the details on the target and said those killed were not Iranians, according to Reuters.

The Associated Press contributed to this report.