According to Lebanese authorities and Hezbollah, at least nine people were killed and more than 2,750 injured on Tuesday when pager devices belonging to a large number of Hezbollah personnel from various units and institutions exploded.

Hezbollah blamed Israel for the attack and vowed to respond. The attack apparently came amid rising tensions between Israel and Hezbollah.

“We hold the Israeli enemy fully responsible for this criminal aggression, which also targeted civilians and resulted in the death of numerous martyrs and the injury of numerous wounded,” Hezbollah said in a statement. “This treacherous and criminal enemy will surely receive its just punishment for this sinful aggression, whether it expects it or not.”

Among the dead and injured were people who were not members of Hezbollah, such as a 10-year-old girl who was killed in the eastern village of Saraain, the Hezbollah-affiliated news agency Al-Ahed News reported. Two Hezbollah members were also killed, the news agency reported.

“These explosions, the causes of which are still unknown, resulted in the martyrdom of a girl and two brothers and the injury of a large number of people with various injuries,” Hezbollah said in a statement.

About 200 of the injuries were critical, meaning they required surgery, the Lebanese Health Ministry said. Most of the injuries affected the face, hands and abdomen, officials said.

Iran’s ambassador to Lebanon, Mojtaba Amani, was one of those who owned one of these pagers and was injured in an explosion on Tuesday, Iranian state television reported.

According to Iranian state television, Amani said in a phone call after the incident that he was “feeling fine and fully conscious.”

According to the Syrian Foreign Ministry, at least 14 people were injured in targeted attacks on Hezbollah members in Syria.

The Lebanese Foreign Ministry said it condemned the alleged Israeli attack and had begun preparing a complaint to the Security Council.

The Lebanese Council of Ministers collectively condemned “this criminal Israeli aggression, which constitutes a grave violation of Lebanese sovereignty and a crime by any standard,” adding that “the government immediately initiated all necessary contacts with the countries concerned and the United Nations to make them aware of their responsibility regarding this ongoing crime.”

The United Nations Special Coordinator for Lebanon condemned the attack on Lebanon, calling it a “highly worrying escalation in an already unacceptably unstable context” in a statement from the UN Office of the Secretary-General’s Spokesperson.

Hezbollah said it was conducting a “security and scientific investigation to determine the causes that led to these simultaneous explosions.”

Tuesday’s events in Lebanon also sparked high-level contacts between the United States and Israel, according to a U.S. official.

The United States apparently played no role in the attack on Hezbollah and did not give any warning before the attack, said State Department spokesman Matthew Miller. He also declined to comment on who might be behind it, saying only that the government was “gathering information” on the incident.

Miller declined to say whether the government had any information that cast doubt on Hezbollah’s claim that Israel was behind the explosions. He said only that he did not want to comment “either way.” The Israeli government has so far refused to comment on the matter.

The White House also said it had no prior knowledge of the attack and did not want to speculate about who was behind it, said press spokeswoman Karine Jean-Pierre.

This attack comes as US diplomats work hard to prevent an escalation on Israel’s northern border and amid fears that a full-scale war between the country and Hezbollah, which has a huge stockpile of missiles, could engulf the entire region. Secretary of State Antony Blinken happens to be on his way to the region and is scheduled to land in Egypt on Tuesday evening.

US Defense Secretary Lloyd Austin and Israeli Defense Minister Yoav Gallant spoke again on Tuesday after speaking on Monday.

The aim of the latest conversation was to “discuss ongoing tensions in the Middle East and threats to Israel, including the Houthi rocket attack over the weekend,” said Pentagon spokesman Major General Pat Ryder.

Ryder said America’s main focus was to ensure tensions in the region do not escalate.

“We firmly believe that tensions on the Israeli-Lebanese border can be reduced through diplomacy,” he said.

A U.S. official said Iran and Hezbollah would likely retaliate for the attack, but it may take some time for them to assess what happened.

The Lebanese Ministry of Health issued a statement on Tuesday instructing all hospitals in various regions of Lebanon to be on high alert and increase their operational readiness to meet the rapid need for emergency medical care.

The ministry noted that preliminary information indicated that “the injuries were related to the explosion of wireless devices in the possession of the injured.”

The ministry also called on all citizens who own a pager to dispose of them immediately.

The Lebanese Red Cross said in a post on its official X-account that it had deployed “more than 30 ambulances” to help treat and evacuate “the injured as a result of the numerous explosions in the south, in the Bekaa Valley and the southern suburbs of Beirut.”

The group also added that “50 additional ambulances and 300 paramedics are on standby to help evacuate the victims.”

About 100 hospitals have admitted injured people, Lebanon’s Health Ministry said. The agency said hospitals in Beirut and its southern suburbs were full and patients had been transferred to hospitals outside the region.

Back in February, Hezbollah leader Hassan Nasrallah had called on his members to refrain from using mobile phones: “I am calling for the renunciation of mobile phones at this time, which are considered a lethal weapon.”

ABC News’ Luis Martinez, Shannon K. Kingston and Anne Flaherty contributed to this report