In recent weeks, lawmakers have circulated bills to curtail the activities of non-government organizations, while a rival hard-line activist group has launched an even fiercer campaign that accuses opponents of being spies and foreign agents. Even the country's president, a member of the ruling Likud party, has come under fire, with nationalists accusing him of coddling hostile groups.

The climate is testing Israel's democratic ideals at a time when the country is feeling pressured at home by public anger over the continuing violence and abroad by growing international criticism of its policies toward the Palestinians. This sense of frustration and isolation is fueling what some say is a siege mentality that perceives opposition activists as the enemy.

"They are using the fear of the street to manipulate more and more hateful politics ... against everyone who has the courage to stand up and say we are going in the wrong direction," said Ishai Menuchin, director of the Public Committee Against Torture in Israel, a group that has called for investigating possible war crimes by the Israeli military.

Menuchin is one of four human-rights activists singled out in a video and newspaper ad published this week by the hawkish non-governmental group Im Tirtzu, which accuses the activists of being foreign agents and undermining the country because their groups receive foreign funding.