DOHA/JERUSALEM, Sept. 9 (Xinhua) -- Israel launched an unprecedented airstrike in the Qatari capital of Doha on Tuesday, targeting a building used by senior Hamas officials in what Israeli authorities described as an attempt to assassinate leaders of the group.

Hamas said Tuesday evening that the attack occurred while its delegation was discussing a new ceasefire proposal presented by U.S. President Donald Trump. According to the group, the negotiating team survived, but six others were killed.

The movement identified the Palestinian victims as Jihad Lubad, office director of Hamas political bureau member Khalil al-Hayya; Hammam al-Hayya, son of Khalil al-Hayya; and escorts Abdullah Abdulwahid, Moamen Hassouna, and Ahmed al-Mamlouk. It also confirmed the death of Badr Saad Mohammed al-Humaidi, a member of Qatar's Internal Security Force.

Israeli authorities did not immediately confirm who was killed. In a joint statement, the Israeli military and the Shin Bet security agency said the strike targeted Hamas leaders "directly responsible for the Oct. 7 massacre" and used "precise munitions and intelligence" to limit civilian harm.

Prime Minister Benjamin Netanyahu called it "a wholly independent Israeli operation." "Israel initiated it, Israel conducted it, and Israel takes full responsibility," he said in a statement released by his office.

White House press secretary Karoline Leavitt told reporters later in the day that the Trump administration was informed by the U.S. military that Israel was striking Hamas targets, "which very unfortunately, was located in a section of Doha, the capital of Qatar."

Leavitt said that Trump "immediately directed Special Envoy Steve Witkoff to inform Qatar of the impending attack, which he did."

However, Qatar denied having prior knowledge, calling such claims "baseless." "The call from a U.S. official came during the sound of explosions caused by the Israeli attack in Doha," Foreign Ministry spokesperson Majed bin Mohammed Al Ansari said in a post on X. The ministry condemned the strike as a "serious threat" to citizens and residents, a violation of sovereignty, and announced the suspension of ongoing negotiations.

Eyewitnesses reported loud explosions and plumes of smoke rising over the Qatari capital. Qatar's Interior Ministry said specialized teams had secured the site and that "the situation is safe."

An Israeli official, speaking with Xinhua on condition of anonymity, said more than a dozen warplanes took part and at least 10 bombs were dropped on the building. Preparations for the strike had been ongoing for months, the official said.

Preparations for the operation were accelerated on Monday, "following the deadly attacks in Jerusalem and Gaza," Netanyahu and Defense Minister Israel Katz said in a joint statement. They referred to a shooting attack by two Palestinian men from the occupied West Bank at a Jerusalem bus stop that killed six and a clash in Gaza that killed four Israeli troops on Monday. They said the airstrikes were carried out "precisely and optimally."

The attack drew swift international condemnation. UN Secretary-General Antonio Guterres condemned the strike as a "flagrant violation" of Qatar's sovereignty. "We are just learning about the Israeli attacks in Qatar, a country that has been playing a very positive role to achieve a ceasefire and the release of all hostages," he told reporters in New York.

He added, "I condemn this flagrant violation of the sovereignty and territorial integrity of Qatar. All parties must work towards achieving a permanent ceasefire, not destroying it."

Saudi Arabia also criticized what it called continued Israeli violations in the region, citing recent strikes in Syria's Homs and Latakia governorates as breaches of international law and the 1974 Disengagement Agreement.

Iranian Foreign Ministry spokesman Esmaeil Baghaei denounced the Doha strike as "extremely dangerous, criminal and in violation of the UN Charter," saying it was part of Israel's "continued crimes" against international law.

Other countries and organizations, including Egypt, Jordan, Trkiye, and the Arab League, also rushed to condemn the Israeli attacks.

In a statement, the Hostages and Missing Families Forum, which represents families of hostages still held in Gaza, said they were following developments in Doha "with deep concern and grave fear."

"The chance of bringing them back is now more uncertain than ever, with one absolute certainty -- their time is running out," the families said. "It is time to end the war."

"I am trembling with fear," Einav Zangauker, whose son Matan is among the hostages, wrote on social media. She said the attack could destroy the chances for a deal and accused Netanyahu of repeatedly "sabotaging the deal."