WASHINGTON (AP) — President Joe Biden’s efforts to tamp down tensions in the escalating war between Israel and Hamas faced massive setbacks even before he departed for the Middle East on Tuesday.

Jordan called off the president’s planned summit with Arab leaders after a deadly explosion at a Gaza hospital killed hundreds.

Biden now will visit only Israel and will postpone his travel to Jordan, a White House official says.

The postponement of the Amman summit comes after Palestinian leader Mahmoud Abbas withdrew in protest of the attacks, which the Hamas-run Health Ministry in Gaza blamed on an Israeli airstrike.

The Israeli military said it had no involvement and pinned the blame on a misfired Palestinian rocket.