Lebanese have been receiving phone messages periodically for more than a year asking people to view a Web site or call if they have information on missing Israeli soldiers, including Ron Arad, whose plane was shot down over Lebanon in 1986.
The Web site, 10million.org, belongs to a foundation set up by the Israeli government and offers a US$10 million reward.
An army statement said Saturday that the messages were a violation of Lebanese sovereignty. It said any response would be considered "clear collaboration" with Israel.
Israel has in the past refused to say if it was behind the calls.