The Syrian civil war has heightened sectarian tensions within Lebanon, particularly between Sunni and Shia Muslims, many of whom support opposing sides and have entered the conflict in large numbers. Hezbollah leader Sheikh Hassan Nasrallah announced on May 25 that Hezbollah would openly support President Bashar al-Assad's forces in fighting the insurgency in Syria. Some Sunni leaders in Lebanon have likewise at various points in time called for Jihad against the Assad regime in Syria, and urged Lebanese to join.