The United Nations chief is demanding a halt to the escalation of “tit-for-tat violence” that he warned is leading people in the Middle East “straight over the cliff.”

Secretary-General Antonio Guterres told an emergency meeting of the U.N. Security Council Wednesday that in just a week the alarming situation in Lebanon has gone from bad “to much, much worse.”

The U.S. has imposed sanctions on an Iranian man and three Chinese firms that Washington believes helped the Houthi militant group acquire materials needed to manufacture and deploy advanced missiles and drones against the U.S. and its allies.

Iranian citizen Hasan Ahmad Hasan Muhammad al-Kuhlani is named in the sanctions announced Wednesday. He is accused of facilitating weapons smuggling for the Houthis.

The Health Ministry in Gaza said at least 51 people were killed and 82 wounded in the operation in Khan Younis that began early Wednesday. Records at the European Hospital show that seven women and 12 children, as young as 22 months old, were among those killed.

Another 23 people, including two children, were killed in separate strikes across Gaza, according to local hospitals.

World shares were mixed on Wednesday, with European benchmarks mostly higher. Hong Kong's Hang Seng soared more than 6% while other Asian markets retreated as tensions escalated in the Middle East.

Oil prices extended gains after Iran fired dozens of missiles into Israel, potentially raising the risk of disruptions to supplies. That news overshadowed an upbeat report showing U.S. job openings rose unexpectedly in August as the American labor market continued to show resilience.

A dog clings to Hussein Hamza inside a car as he pans his camera around to show the aftermath of an Israeli airstrike in southern Lebanon.

"Poor thing. Look at this, he's clinging to me out of fear," Hamza says in the video he posted online. "A missile hit here," he said, his voice shaking.

When Israel bombed buildings outside the southern Lebanese city of Sidon, Mohamed Arkadan and his team rushed to an emergency unlike anything they had ever seen.

About a dozen apartments had collapsed onto the hillside they once overlooked, burying more than 100 people. Even after 17 years with the civil defense forces of one of the world's most war-torn nations, Arkadan was shocked at the destruction. By Monday afternoon — about 24 hours after the bombing — his team had pulled more than 40 bodies, including children's, from the rubble, along with 60 survivors.

Egypt’s top diplomat on Tuesday deplored Israel’s “serious escalation” in southern Lebanon, after the Israeli military said it launched a “limited and focused” ground incursion.

Foreign Minister Badr Abdelaty warned that Israel’s escalation threatens to inflame the entire region “in a way that will lead to dire security and humanitarian consequences,” according to a statement from the Egyptian Foreign Ministry.

The Israeli military said it launched a fresh strike on south Beirut on Tuesday.

"The IDF (Israeli military) conducted a precise strike in Beirut," the statement said, without offering details, while local media outlets reported simultaneous strikes on an apartment in a building in Jnah near al-Zahraa Hospital, and on another region in Beirut's southern suburbs.

"The United States has indications that Iran is preparing to imminently launch a ballistic missile attack against Israel," a senior White House official told AFP on Tuesday, speaking on condition of anonymity.

"We are actively supporting defensive preparations to defend Israel against this attack," the official said in a statement, warning that such an action "will carry severe consequences for Iran."

The Israeli army has been carrying out secretive ground operations to destroy Hezbollah infrastructure in Lebanese villages close to the border for the past year, military spokesman Rear Adm. Daniel Hagari said Tuesday.

He said that the current ground maneuvers in Lebanon are an expansion of the previous year’s operations.