GAZA/BEIRUT - Hamas announced a freeze on ceasefire negotiations with Israel after the faction's deputy chief, Saleh al-Arouri, was killed Tuesday evening in an Israeli attack in Lebanon, a Palestinian source told Xinhua.

"We have informed the brothers in Qatar and Egypt of the freezing of negotiations," the source said on condition of anonymity. Qatar and Egypt have been mediating a ceasefire between Israel and Hamas.

The source added that Hamas, at war with Israel, rejected any talks about reaching a ceasefire in the Gaza Strip amid escalated Israeli aggression and "assassination schemes" against Palestinian leaders.

Earlier, a Hamas source told Xinhua that several aides of al-Arouri, deputy head of the Hamas politburo, were also killed in the Israeli attack targeting a Hamas office in the southern suburb of the Lebanese capital of Beirut.

In a statement, Hamas confirmed that seven of its members were slain in the Israeli attack, slamming it as a "barbaric and heinous" terrorist act, a violation of Lebanon's sovereignty, and an expansion of Israeli aggression against Palestine and its people.

Lebanese armed group Hezbollah said the attack was a serious assault on the Lebanese people, security, and sovereignty.

"This crime will never pass without response and punishment," it said in a statement, warning that the attack signaled "a dangerous development" in the current Israel-Hamas conflict.

There was no immediate comment from Israel on the incident, but Israeli media, citing senior officials, said that the country was on high alert against "a significant retaliation" by Hamas or its Iranian-backed ally, Hezbollah, including the launching of precision weapons at Israeli cities.

"The IDF (Israel Defense Forces) is in a very high state of readiness in all arenas, both in defense and offense. We are highly prepared for any scenario," IDF Spokesperson Daniel Hagari said during a briefing to reporters.

Iran on Tuesday condemned Israel's "despicable" move of assassinating al-Arouri, as well as two commanders of the Al-Qassam Brigades, the Hamas armed wing, in the drone strike in Beirut.

Lebanese Prime Minister Najib Mikati also strongly condemned the Israeli attack that rocked the southern suburbs of Beirut on Tuesday, according to Lebanon's National News Agency (NNA).

"The explosion is a new Israeli crime aimed at inevitably dragging Lebanon into a new phase of confrontation, following the daily ongoing assaults in the south, resulting in a significant number of martyrs and wounded individuals," Mikati said in a statement.

In recent weeks, Israeli officials threatened to assassinate Hamas leaders in Palestinian territories and beyond, particularly al-Arouri, who was accused by Israel of directly being responsible for the "Al-Aqsa Storm" attack on southern Israel on Oct. 7, which sparked the current Israel-Hamas conflict.

Al-Arouri, 57, is considered one of the prominent Hamas leaders, and a founder of the al-Qassam Brigades and its cells in the West Bank.

He was imprisoned in Israel for more than 18 years and was deported by Israeli authorities from Palestinian territories upon his last release in 2010. In the same year, he was elected as a Hamas politburo member.

Al-Arouri became the No. 2 in the top Hamas leadership body in 2017.