Iran's foreign ministry rejected Monday as "worthless" Washington's claims that a drone attack targeting a tanker off the coast of India was "fired from Iran".
Saturday's targeting of a Japanese-owned chemical tanker came amid a flurry of drone and missile attacks by Yemen's Iran-backed Huthi rebels in the Red Sea in solidarity with Palestinians in Gaza, where Israel is battling Hamas militants.
The Pentagon later openly accused Tehran of the attack.
"We declare these claims as completely rejected and worthless," said foreign ministry spokesman Nasser Kanani when asked about the US accusations.
"Such claims are aimed at projecting, distracting public attention, and covering up for the full support of the American government for the crimes of the Zionist regime (Israel) in Gaza," he added.
The Gaza Strip has endured over 11 weeks of Israeli air and ground attacks that have killed more than 20,400 people, mostly women and children, according to the health ministry in the Hamas-run coastal territory.
Israel has vowed to crush Hamas after the Palestinian militant group carried out a cross-border attack on October 7 that killed around 1,140 people in Israel, mostly civilians, according to an AFP tally based on Israeli figures.
Palestinian militants also abducted about 250 people, 129 of whom Israel says remain in Gaza.
Kanani also slammed as "repetitive" and "threadbare" recent remarks by UK Foreign Secretary David Cameron who branded Iran a "malign influence in the region and the world" and urged a "set of deterrent measures against" it.
The Islamic republic, which supports Hamas financially and militarily, has hailed the October 7 attacks as a "success" but denied any direct involvement.
Yemeni rebels' recent attacks on shipping vessels in the Red Sea have prompted major firms to reroute their cargo vessels around the southern tip of Africa, a much longer voyage with higher fuel costs.
Iran has repeatedly dismissed US and Israeli accusations that Tehran was involved in attacks by the Huthis, saying the group was acting on its own.