A senior Iranian official says the country can "easily" hit US warships in the Gulf, the latest in days of sabre-rattling between Washington and Tehran.
The comment by the deputy for parliamentary affairs of the elite Revolutionary Guards comes as Iran's top diplomat works to counter US sanctions and salvage a nuclear deal denounced by President Donald Trump.
Tensions have risen in recent days amid concerns about a potential US-Iran conflict. Earlier this week, the United States pulled some diplomatic staff from its embassy in Baghdad following weekend attacks on four oil tankers in the Gulf.
"Even our short-range missiles can easily reach (US) warships in the Persian Gulf," Mohammad Saleh Jokar was quoted by Fars news agency as saying on Friday.
"America cannot afford the costs of a new war, and the country is in a bad situation in terms of manpower and social conditions," he added.
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Washington has increased economic sanctions and built up its military presence in the region, accusing Iran of threats to US troops and interests.
Tehran has described those steps as "psychological warfare" and a "political game".
In Washington, a senior administration official said the US is "sitting by the phone" but has heard no message yet from Iran that it is willing to accept Trump's overtures for direct talks.
"We think they should de-escalate and come to negotiations," the official, who declined to be identified, told a small group of reporters.
Trump has urged Iran's leadership to hold talks over its nuclear program and regional influence amid rising tensions between the two countries that have fanned fears of armed conflict after the US deployed an aircraft carrier group to the region.
Iranian army chief Major General Abdolrahim Mousavi warned any action would be met with retaliation.
"If the enemy miscalculates and commits a strategic error, it will receive a response which will make it regret (its action)," the semi-official news agency Mehr reported.
Senior lawmaker Heshmatollah Falahatpisheh used Twitter to call for an Iran-US "red desk" to help prevent a war.
"Top authorities in Iran and America have rejected a war, but third parties are in a hurry to destroy a large part of the world. A red desk should be set up in Iraq or Qatar with officials from the two sides ... to manage tensions," said Falahatpisheh, head of parliament's national security committee.
Supreme Leader Ayatollah Ali Khamenei said this week Tehran would not negotiate another nuclear deal after Washington last year quit a 2015 international pact that put curbs on Iran's potential pathway to build a nuclear bomb in exchange for the lifting of international sanctions.