Obama Tells Israeli Prime Minister He Has 'Serious' Concerns About Increasing Palestinian Casualties

President Barack Obama told Israeli Prime Minister Benjamin Netanyahu he has "serious concerns" about the number of casualties on both sides of the ongoing conflict of Gaza, according to a White House readout of the Sunday morning phone call.

The official release specifically noted that concern included "increasing Palestinian civilian deaths."

"The President discussed Israel's ongoing military operation, reiterated the United States' condemnation of attacks by Hamas against Israel, and reaffirmed Israel's right to defend itself. The President also raised serious concern about the growing number of casualties, including increasing Palestinian civilian deaths in Gaza and the loss of Israeli soldiers," the readout said.

Tensions between the two sides have been high since the kidnap and murder of three Israeli teens in June and subsequent rocket attacks against Israel. Since Israel began a major offensive against Hamas in Gaza two weeks ago, 336 Palestinians have died, according to a Saturday report in the New York Times. The Jerusalem Post reported Sunday that 18 Israeli soldiers have died in the fight.

Obama also told Netanyahu that Secretary of State John Kerry will soon travel to the region to seek a ceasefire.

"The President underscored that the United States will work closely with Israel and regional partners on implementing an immediate ceasefire, and stressed the need to protect civilians-in Gaza and in Israel," the readout continued.