The fighting between Israel and Iran intensified overnight, as both nations kept up their attacks, killing civilians and raising concern among world leaders that the biggest battle between old enemies could lead to a broad regional conflict.

Israel and Iran have begun a new round of attacks, as the conflict between the two heavily armed rivals enters its fourth day.

US stocks closed higher as Iran aims to deescalate the clash with Israel. Oil prices eased. Fed meets on rates this week. No one expects a rate cut.

Saudi Arabia is also working behind the scenes to promote a ceasefire framework, a source told The Jerusalem Post.

Smoke and missiles have lit up the skies in Israel and Iran in a fierce standoff triggered by fears over Tehran’s expanding nuclear program. Since June 13, hundreds of military strikes have been exchanged as the two nations remain locked in a conflict that shows no signs of abating.

The death toll grew Sunday as Israel and Iran exchanged missile attacks for a third consecutive day, with Israel warning that worse is to come. Israel targeted Iran’s Defense Ministry headquarters in Tehran and sites it alleged were associated with Iran’s nuclear program,