Israel's shekel weakened on Monday, hitting a key level of four per U.S. dollar for the first time since 2015, hurt by investor jitters over Israel's war with Palestinian militant group Hamas.

Since the start of the hostilities on Oct 7, the shekel has weakened roughly 4% against the greenback. It was last down 0.6% at 3.9980 per dollar.

Part of the shekel's weakness in recent days is due to investors starting to price in Bank of Israel rate cuts starting on Oct. 23.

(Reporting by Steven Scheer in Jerusalem; Additional reporting by Gertrude Chavez-Dreyfuss in New York.)