Iran's Supreme Leader Ali Khamenei said the visit of US President Joe Biden and other Western leaders to occupied territories indicates they fear the Zionist regime was falling apart.
Khamenei said the US manages the war, describing Washington as "a definite accomplice of the Zionist criminals."
Agence France Presse quoted Khamenei as saying the hands of the US "were tainted with the blood of the oppressed, children, patients, women, and others."
"The United States is in some way directing the crime being committed in Gaza."
Khamenei was speaking before a group of officials and commanders of the armed forces in his third speech since the outbreak of the war between Hamas and Israel in the Gaza Strip.
On October 10, Khamenei denied his country's involvement in the massive attack launched by Hamas against Israel but renewed his country's support for armed Palestinian groups.
Khamenei underlined that "the occupying regime is taking revenge on the people of Gaza because of the blows it received from the Palestinian fighters," adding: "Victory belongs to the Palestinian nation both in this matter and in the future."
Later, President Ebrahim Raisi repeated the same accusations, saying the US was complicit in the crimes of Israel.
Hours after Khamenei's speech, Revolutionary Guard Deputy Commandant for Operations Abbas Nilforoushan said CENTCOM is responsible for managing Israel's affairs.
Tasnim agency quoted Nilforoushan as describing the al-Aqsa Flood operation as a mini-resistance operation to remove the Zionist entity, adding that after the Zionists fled the occupied territories, CENTCOM took over.
Iran and Western powers have exchanged warnings of expanding the war. Tehran has said that continued bombing of the Gaza Strip would lead to an expansion of the war.
On Tuesday, Secretary of State Antony Blinken warned that Washington would act swiftly and decisively if Iran or its proxies attacked US personnel anywhere.
Iran's Defense Minister Mohammad-Reza Ashtiani responded quickly, saying his country would give a decisive, strong response to any miscalculation or mistake by enemies.
Earlier this week, Reuters quoted two unnamed Iranian officials as saying Iran's rulers can't afford a direct involvement in the conflict while struggling to quell mounting dissent at home, driven by economic woes and social restrictions.
"For Iran's top leaders, especially the supreme leader, the utmost priority is the survival of the Islamic Republic," a senior Iranian diplomat said.
"That is why Iranian authorities have used strong rhetoric against Israel since the attack started, but they have refrained from direct military involvement, at least for now."