UNITED NATIONS/BEIRUT - The United Nations strongly condemns Israel's strikes across Lebanon that resulted in significant civilian casualties, Farhan Haq, deputy spokesperson for the UN secretary-general, said Wednesday.

"The UN strongly condemns the loss of civilian lives," Haq told a daily briefing, adding that the United Nations continues to call on all sides to avail themselves of diplomatic channels, cease hostilities and recommit to the full implementation of Security Council resolution 1701 (2006).

The ceasefire between the United States and Iran offers an opportunity to prevent further loss of lives between Lebanon and Israel, Haq said, urging all concerned to abide by the ceasefire.

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As UN peacekeepers continue to be impacted by hostilities, the United Nations again urges all actors to uphold their obligations under international law and to ensure the safety and security of UN personnel and property at all times, he added.

"We stress again that any intimidation or interference in the Mission's (the United Nations Interim Force in Lebanon) Security Council-mandated tasks must stop immediately," he said, referring to the Israel Defense Forces' detention of a UN peacekeeper on Tuesday.

Emphasizing there is no military solution to the conflict, Haq said, "Now is the time to pursue talks to resolve outstanding differences and work towards a permanent ceasefire and a long-term solution to the conflict." 

Meanwhile, Lebanon's Hezbollah group said in a statement on Thursday that it fired rockets at northern Israel in response to Israel's "ceasefire violations."

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"This response will continue until the Israeli-American aggression against our country and our people ceases," the group said in a statement.

Israel carried out its heaviest strikes across Lebanon since the current round of conflict with Hezbollah broke out last month, killing at least 254 people and injuring 1,165 others on Wednesday, hours after a two-week US-Iran ceasefire was announced. Both Israel and the United States have maintained that Lebanon is not included in the truce.

Israel's military said Wednesday's attack was its largest coordinated strike on Lebanon since it started a new military operation against the country on March 2, "targeting more than 100 Hezbollah command centers and military sites.”

The United Nations High Commissioner for Human Rights Volker Turk condemned the attack, calling the casualty figures appalling.

"The scale of the killing and destruction in Lebanon today is nothing short of horrific," he said in a statement. "Such carnage, within hours of agreeing to a ceasefire with Iran, defies belief. It places enormous pressure on a fragile peace, which is so desperately needed by civilians."