WASHINGTON (BLOOMBERG) - President Joe Biden ramped up efforts to calm Israeli-Palestinian tensions and urged the protection of civilians, including children, after an Israeli air strike targeted media offices in Gaza.

Biden told Israeli Prime Minister Benjamin Netanyahu of his "grave concern" about the ongoing violence, the White House said in a readout. He reaffirmed, though, Israel's right to defend itself against "Hamas and other terrorist groups in Gaza."

Speaking with Palestinian Authority President Mahmoud Abbas for the first time since taking office, Biden "underscored his strong commitment to a negotiated two-state solution" to resolve the Israeli-Palestinian conflict. He stressed the need for Hamas to cease firing rockets into Israel, the White House said.

The conversations followed an air strike on Saturday (May 15) that targeted and destroyed a 12-storey building in Gaza City that housed the offices of the Associated Press and other media outlets as well as residential apartments.

Hours later, Israel bombed the home of Khalil al-Hayeh, a top leader of Gaza's ruling militant Hamas group, the AP reported, as weeks of tension continue to flare.

Biden "raised concerns about the safety and security of journalists and reinforced the need to ensure their protection," the White House said. He also noted the loss of civilian lives, including children, in the current conflict.

Israel's military said the building targeted in Gaza City was an important base of operations for Hamas military intelligence.

Civilians were warned of the attack and given a chance to evacuate the building, it said on Twitter. Hamas and Islamic Jihad used this time to remove items, a price Israel was prepared to pay in order not to harm civilians, it said.

The Associated Press said it has operated from the building for 15 years, and had no indication that Hamas was present or active there.

The building's owner received a warning from the military that a strike would come within an hour, and AP staffers and other occupants evacuated safely.

Abbas said he'd urged Biden to intervene to stop the Israeli strikes, and said the Palestinians were ready to work with the Middle East Quartet, which is comprised of envoys from the EU, Russia, the US and the United Nations.

Netanyahu said in a statement about the call with Biden that Israel "is doing all it can to avoid harming those who are uninvolved."

The Vienna-based International Press Institute called Saturday's strike on the media building "completely unacceptable, even during an armed conflict."

"There is no doubt that Israeli forces were aware that the media offices would be destroyed," said John Daniszewski, chairman of IPI's North American Committee and IPI special representative for journalist safety.

Separately, a dozen Jewish members of Congress wrote to Biden on Friday condemning the ongoing violence and urging the US to address Israel's "deepening occupation" in East Jerusalem.

Concern also mounted in Europe, where a top EU official was reported to be "in intense efforts" to find a way to de-escalate the current conflict.

Josep Borrell, High Representative for Foreign Affairs and Security Policy, has both condemned Hamas' "indiscriminate" firing of rockets into Israel and stressed that Israel "must act proportionately."

US Defence Secretary Lloyd Austin spoke Saturday with his Israeli counterpart Benny Gantz.

Austin "strongly condemned the continued onslaught of attacks by Hamas and other terrorists groups targeting Israeli civilians. The Secretary shared his view on the need to restore calm," according to a readout from Pentagon press secretary John Kirby.

More than 145 Palestinians in Gaza, including children, and an estimated 10 Israelis have died in the recent fighting, with hundreds of buildings damaged or in ruins. Israel has indicated that its bombardment of Gaza will continue until it determines Hamas' capabilities have been significantly degraded.

Deputy Assistant US Secretary for Israel-Palestinian Affairs Hady Amr arrived on Friday to talk to both sides as part of international peace efforts. The United Nations Security Council has scheduled an emergency meeting on the conflict for Sunday morning.