Dubai, UAE. Israel launched a daylight strike on Iran’s capital Saturday, sending smoke billowing over downtown Tehran in an attack that appeared to target an area near the offices of Supreme Leader Ayatollah Ali Khamenei.

The United States participated in the operation, according to a US official and another person familiar with the matter who spoke on condition of anonymity to discuss sensitive military details. The extent of American involvement was not immediately clear. The White House declined to comment.

It was also unclear whether the 86-year-old Khamenei was present at the time of the strike. He has not appeared publicly in recent days as tensions with Washington have intensified. The attack comes as the United States has deployed fighter jets and warships to the region in an effort to pressure Iran over its nuclear program.

Roads leading to Khamenei’s compound in central Tehran were closed by authorities as additional explosions were heard across the city.

President Donald Trump has sought a deal to curb Iran’s nuclear program, viewing Tehran as weakened by domestic unrest following nationwide protests. Iran has said it wants to avoid war but insists it has the right to enrich uranium and has refused to negotiate over its long-range missile program or its support for armed groups such as Hamas and Hezbollah.

It was not immediately clear whether Iran would retaliate. Tehran has previously warned that US personnel and bases in the region would be targeted in the event of an attack.

Israeli Defense Minister Israel Katz said the strike was carried out “to remove threats” but did not provide further details.

In Israel, several hospitals activated emergency protocols, moving patients and surgeries to underground facilities.

Witnesses in Tehran reported hearing an initial blast near Khamenei’s office. Iranian state television later acknowledged the explosion but did not provide details on its cause.

Sirens sounded across Israel as the country closed its airspace. The Israeli military said it issued a “proactive alert to prepare the public for the possibility of missiles being launched toward the state of Israel.”

Further explosions were reported in Tehran after Israel confirmed it was carrying out attacks. Iranian authorities did not immediately release casualty figures.

Iran later shut down its airspace, and mobile phone services were disrupted.