Shortly after, US Central Command told Al Jazeera that the US military had not carried out any attacks on Iran in the past few hours.

The United States and Iran have been exchanging missiles since Tuesday, with Tehran also striking US military bases in the Persian Gulf, including Qatar, Bahrain and Kuwait. The retaliatory strikes by the two countries have further jeopardized a fragile ceasefire agreement reached in mid-June.

Mehr News Agency did not provide any detailed information about the cause of the explosion, damage or casualties.

Bushehr's deputy governor for political and security affairs, Ehsan Jahanian, told state media IRNA that the explosion in the city was caused by air defense systems.

Jahanian also said a "projectile" or missile-like object hit a military base on the outskirts of Bushehr.

The war is 'not over'

Shortly after the news from Iran, Israeli Prime Minister Benjamin Netanyahu said he had spoken by phone with US President Donald Trump. "During the phone call, they agreed to maintain coordination between the two countries in various areas," according to a statement released by the Prime Minister's Office.

The statement also said that Trump briefed Netanyahu on the latest situation on "US actions in the Persian Gulf."

Earlier on Thursday, Netanyahu said at an air force graduation ceremony at Hatzerim Air Base in southern Israel, "The (Iran) war is not over. There are new challenges."

According to a report in the daily Yedioth Ahronoth, Netanyahu is heard saying, "Maintaining dominance over the skies is a fundamental pillar of Israel's national security policy. It is crucial for maintaining stability in the turbulent Middle East."

Israeli army chief of staff Yal Zamir also said the military operation against Iran "is not over."

The head of the Israeli forces that have unleashed atrocities in the Middle East said in his brief statement, "We have new plans on the table. It seems that a major operation still awaits us. Be prepared."

Israel's defense minister has said that Israel is ready to attack Iran if necessary.

Israeli Defense Minister Israel Katz, who has made provocative statements at various times, said, "The army is ready to start a war to regain air superiority, strike Iran again, and eliminate the threat. They are on alert. We are ready to strike a third time if necessary."