Local media in Iran said Monday that a "hostile drone" was shot down over the capital Tehran during the new round of fighting with Israel.

"A hostile drone belonging to the American-Zionist enemy was targeted and destroyed by air defenses in the skies over Tehran," the Mehr news agency reported, without elaborating.

The Israeli military said Monday it had struck and dismantled Iranian defense systems deployed across several areas in the country.

"Recently, defense systems were deployed in numerous areas across Iran as part of the regime's efforts to restore its detection and defense capabilities, which were degraded during Operation Roaring Lion," the military said.

Iran said Monday that the United States held responsibility for the resumption of fighting with Israel, saying Israel's actions "cannot be separated" from U.S. policy.

"Without a doubt, as I said, the actions of the Zionist regime in the region cannot be separated from U.S. policies," foreign ministry spokesman Esmaeil Baqaei said at a press conference in Tehran attended by AFP.

The Israeli military has vowed to press ahead with its military campaign in Lebanon and said it would step up operations against Hezbollah.

"The (Iranian) regime is attempting to establish a new equation through direct attacks on Israeli territory in response to IDF operations in Dahieh," military spokesman Brigadier General Effie Defrin said Sunday, in a televised statement.

Israel and Iran traded fire on Monday, seriously testing a fragile truce and threatening hopes for a deal to end the Middle East war.

The new attacks, including a strike on an Iranian petrochemical complex, came hours after U.S. President Donald Trump called on Israel to refrain from retaliating against Tehran's missiles.

U.S. President Donald Trump said Sunday he will call Israeli Prime Minister Benjamin Netanyahu to urge him not to retaliate against Iranian missile strikes on Israel, U.S. news outlet Axios reported.

"I am going to call Bibi right now and tell him not to retaliate," Trump was quoted as saying by Axios journalist Barak Ravid in a phone interview, using the Israeli leader's nickname.

Air raid sirens sounded in Israel on Sunday as its military worked to intercept barrages of incoming Iranian missiles for the first time since an April ceasefire took hold in the Middle East war.

The Israeli army reported the attack just hours after Tehran had threatened to retaliate for a new Israeli strike on Beirut's southern suburbs.

The Israeli military said Sunday it uncovered a sprawling tunnel network beneath the Beaufort castle in southern Lebanon, saying it was built to give Hezbollah a fortified strike hub just kilometers from Israeli territory.

Israeli soldiers recaptured the crusader-era castle recently, giving the military a strategic toehold it once occupied for nearly two decades.

Iran threatened to retaliate against the United States and Israel for fresh strikes in Beirut's southern suburbs on Sunday, further dampening hopes for a lasting peace as the Middle East war reached its 100th day.

U.S. President Donald Trump called for "more surgical" strikes against Hezbollah in Lebanon and said he is not demanding the conflict be included in a peace deal with Iran, in an interview broadcast Sunday.

"I'd like to see a more surgical attack on Hezbollah. I think it should be more surgical," Trump told NBC's "Meet the Press," according to a transcript of the interview recorded Friday.