U.S. President Joe Biden will not attend a major United Nations climate summit that begins Thursday in Dubai, United Arab Emirates, skipping an event expected to be attended by King Charles III, Pope Francis and leaders from nearly 200 countries, a White House official said Sunday.

The official, who asked to remain anonymous to discuss the president’s schedule, did not give a reason Biden will not make an appearance at the two-week summit, known as COP28.

But senior White House aides suggested that the war between Israel and Hamas had consumed the president in recent weeks and days, as he pressed for a pause in fighting and release of hostages held by Hamas.