US Secretary of State Antony Blinken on Monday urged Israel and Palestinians to "protect civilians, especially children", reiterating that Israel "as a democracy has an extra burden" to do so.

"We'll continue to conduct intensive diplomacy to bring this current cycle of violence to an end" and "we are ready to lend support, if the parties seek a ceasefire", Blinken told a press conference in Copenhagen.

He reiterated Washington's support for Israel's right "to defend itself", stressing there was "no equivalence between a terrorist group indiscriminately firing rockets at civilians and a country defending its people from those attacks."

"So we call on Hamas and other groups in Gaza to end the rocket attacks immediately."

However, he added that "Israel as a democracy has an extra burden to do everything possible to avoid civilian casualties."

That includes journalists, Blinken said, referring to an Israeli air strike on Saturday that destroyed a building in Gaza housing international media outlets Al Jazeera television and US news agency The Associated Press.

The top US diplomat reiterated Washington's concerns about protecting the media, but stopped short of condemning the strike.

He said Washington had requested Israel provide "additional details regarding the justification" for the strike.

Blinken said he had not personally seen any information shared by Israeli authorities, and therefore did not want to comment on the legitimacy of the strike.

"Israel has a special responsibility to protect civilians in the course of its self-defence, and that most certainly includes journalists," he said.

Blinken also defended Washington's move to block a UN Security Council declaration calling for an end to the hostilities.

"We're not standing in the way of diplomacy," Blinken stressed.