(NewsNation) — Israel continued airstrikes and ground operations in both Lebanon and Gaza on Wednesday, a day after Iran fired a barrage of ballistic missiles into Israel and vowed a more powerful attack if Israel retaliates.

The ground incursion into Lebanon left eight Israeli soldiers dead, seven of which the Israeli military said were killed in two separate attacks.

The Israeli military said seven soldiers were killed in two separate attacks without elaborating. Another seven troops, including a combat medic, were wounded.

Earlier, the military had announced that a 22-year-old captain in a commando brigade was killed in Lebanon, the first Israeli combat death since the start of the incursion. The assaults were among the deadliest against Israeli forces in months.

Tension continue to rise in Middle East

Smoke could be seen rising above the Beirut suburbs, where Israel has been firing at Iran-backed Hezbollah targets. In southern Gaza, Palestinian health officials say an Israeli operation killed at least 51 people.

Hezbollah, widely seen as the most powerful armed group in the region, said its fighters clashed with Israeli troops in two places inside Lebanon near the border. The Israeli military said ground forces backed by airstrikes had killed militants in “close-range engagements” without saying where.

The Israeli strikes in Lebanon and Gaza came hours after Iran fired nearly 200 missiles into Israel, with the military saying most of them were intercepted. Prime Minister Benjamin Netanyahu has vowed to retaliate, saying Iran “made a big mistake” and “will pay for it.”

Despite the prime minister’s words, Hezbollah fired a barrage of rockets near Haifa early Wednesday, which NewsNation’s correspondent on the ground there observed.

Neither side appears willing to back down from the brink, as millions around the globe watch the Middle East seemingly on the edge of an all-out war.

Israeli media reported infantry and tank units operating in southern Lebanon after the military sent thousands of additional troops and artillery to the border.

The Lebanese army said Israeli forces had advanced a short distance across the border and withdrew “after a short period,” its first confirmation of the incursion.

US reaffirms support for Israel

Overnight, the Department of Defense said Secretary Lloyd Austin spoke with the defense minister of Israel, reaffirming the U.S. support for Israel and saying the U.S. is ready to respond if things escalate further.

President Joe Biden on Tuesday warned of severe consequences against Iran for the missile attack, and as many as 43,000 U.S. forces remain stationed in the region. The USS Abraham Lincoln aircraft carrier strike group is operating there, and a second aircraft carrier group is expected to arrive sometime next week.

“The attackers have been defeated and ineffective, and this is testament to Israeli military capability and the U.S. military,” Biden said. “It is also a testament to the intensive planning between the United States and Israel to anticipate and defend against the brazen attack that we expected. Make no mistake: the United States is fully, fully, fully supportive of Israel.”

The ground operations in Lebanon have raised fears of a wider war in the Middle East that could draw in Iran and the United States, which has rushed military assets to the region in support of Israel. Hezbollah, widely seen as the most powerful armed group in the region, and Hamas are both backed by Tehran.

The State Department has stopped short of calling for an evacuation of Americans in Lebanon, but advised Americans there to leave the country by commercial means. Right now, about 500,00 to 600,000 Americans are living in Israel, adding to the concern of a growing war.

Israel criticizes United Nations

Israel also lashed out at the United Nations on Wednesday, declaring Secretary-General António Guterres persona non grata, or banned from entering the country. Foreign Minister Israel Katz accused him of failing to unequivocally condemn the Iranian attack.

Guterres had released a brief statement after the barrage that read: “I condemn the broadening of the Middle East conflict, with escalation after escalation. This must stop. We absolutely need a cease-fire.”

Iranian leader makes first comments since missile attack

Meanwhile, Iran’s Supreme Leader Ayatollah Ali Khamenei slammed the presence of American and European nations in the Middle East in his first remarks since Tehran fired missiles at Israel.

Khamenei said Wednesday that their presence is a source of “conflicts, wars, concerns and enmities” but made no mention of the missile attack the night before.

“Regional nations can manage themselves and … they will live together in peace,” Khamenei was quoted as saying by the official IRNA news agency.

He said Iran is hopeful of getting “rid of the enemies’ evil” and also urged Western nations to “cut their badness.”

The Associated Press contributed to this report.