Israeli military aircraft have dropped leaflets urging Palestinians to stay away from the Gaza-Israel border fence and warning that they endanger their lives if they follow directives of Hamas organizers of weekly protests there.

The leaflets were dropped on Friday, ahead of what's to be the fourth large-scale protest, largely organized by Gaza's rulers from the Islamic militant Hamas, in part to challenge a decade-old border blockade of the territory.

Israel has accused Hamas of using the protests as a cover for carrying out attacks. It has said it will not allow protesters to approach or damage the border fence. Rights groups say orders allowing troops to use potentially lethal force against unarmed protesters are unlawful.

Since March 30, 28 Palestinians have been killed and hundreds wounded by army fire.