China said on Wednesday it strongly condemns Israel's deadly attack on Hamas political leaders in the Qatari capital Doha.

Hamas said the strikes killed six people, including the son of its top negotiator and a Qatari security officer, but that senior leaders survived.

"China strongly condemns the attack... and firmly opposes Israel's violation of Qatar's territorial sovereignty and national security," Foreign Ministry spokesman Lin Jian told a regular news briefing.

"We are deeply concerned that the attack may further heighten regional tensions, and we express dissatisfaction with actions by certain parties that undermine the ceasefire negotiations in Gaza."

US President Donald Trump said he was not notified in advance of the Israeli attack on the Gulf state, a crucial broker in the negotiations between Israel and Hamas on ending the Gaza war and securing the release of hostages held by Palestinian militants.

"I'm not thrilled about the whole situation," Trump said.

"We want the hostages back, but we are not thrilled about the way that went down today."

Trump also said in a post on social media, "This was a decision made by (Israeli) Prime Minister (Benjamin) Netanyahu, it was not a decision made by me.

"I view Qatar as a strong Ally and friend of the US, and feel very badly about the location of the attack."

Israel's United Nations envoy said his country does not always act in the interests of its ally the United States.

"We don't always act in the interests of the United States. We are coordinated, they give us incredible support, we appreciate that, but sometimes we make decisions and inform the United States," Danny Danon told an Israeli radio station.

"It was not an attack on Qatar; it was an attack on Hamas," he said, adding that "the decision is the right one".

Qatar will continue trying to mediate a ceasefire and hostage release in Gaza despite the deadly attack, Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani said.

He said his country reserved "the right to respond to this blatant attack", calling the strike a "pivotal moment" for the region.

In addition to its role in the Gaza negotiations, Qatar is home to a huge US airbase and hosted Trump during a Middle East swing this year.

As Qatar complained about the attack, Trump said he had now directed US Secretary of State Marco Rubio to finalise a defence cooperation agreement with Doha.

Britain, France and Germany also condemned the Israeli air strikes.

French President Emmanuel Macron called them "unacceptable regardless of motive", adding that "the war must not be allowed to spread in the region".

UK Prime Minister Keir Starmer said the attack risked further escalation in the region.

German Chancellor Friedrich Merz called the strikes "unacceptable". (AFP)