Israel remained on high alert Monday, but authorities lifted some emergency measures that had included a ban on some school activities and caps on large gatherings.

The comments by Ayatollah Ahmad Khatami followed a week of escalating tensions that threaten to spill over into a wider conflict between the two bitter enemies.

U.N. Secretary-General Antonio Guterres called for an immediate halt to “all hostile acts” to avoid “a new conflagration” in the Middle East after Israeli forces bombed Iranian targets inside Syria.