WASHINGTON (AP) — Pro-Israel groups are running into rare resistance as they press Congress to back President Barack Obama's call to authorize military strikes on Syria.

The administration has sought and won support for the vote from most of the major pro-Israel groups that have traditionally been most effective in promoting legislation designed to enhance Israel's security.

Yet, officials with organizations considered to be some of the most influential lobbyists on Capitol Hill say they are finding it difficult to overcome opposition to the use of force among skeptical lawmakers and their war-weary constituents.

While winning widespread condemnation of Syria's use of chemical weapons, their argument that action is a moral imperative and crucial for Israel's security appears to be falling on deaf ears, even among some of the staunchest advocates for Israel.