U.S. policymakers should not assume Saudi Arabia will "act in lockstep" with the United States in countering Iran's influence in the Arab world, a Rand Corp. report said Tuesday.

While the Saudis often are viewed as a "confrontational proxy" against Iran, the Saudi government in Riyadh has demonstrated a tendency to hedge its bets, the research organization said.

Instead of lining up against Iran, the Saudi kingdom is pursuing a nuanced approach that incorporates elements of accommodation and engagement, the report said.

There is a rivalry between Saudi Arabia and Iran but they also work together on various issues, including economic issues and regional security, Alireza Nader, one of the authors, said in an interview.

"It is not a black and white relationship," Nader said.

While Iranian President Mahmoud Ahmadinejad has vowed to erase Israel from the map, the Saudis have won widespread Arab support for a peace plan offering Israel recognition in exchange for all Arab land lost in the 1967 Mideast war.

Iran is challenging the Saudis' claim to leadership on Arab issues, particularly Palestine, the report said, while Saudi King Abdullah is trying to isolate Iranian rejection of Israel.

Overall, the report said, the United States should encourage Saudi outreach to Iran while working to resolve the two countries' differences, particularly on the Arab-Israeli front.

Tensions between Iran and Saudi Arabia are long-standing. Iran continues to regard Riyadh as America's principal local proxy while Saudi Arabia harbors a deep distrust of Iran, the report said.

But when necessary, the two countries have cooperated when their interests intersect.

"Both sides are careful not to create too much instability in the Persian Gulf," Nader said. And, he added, as Iran's nuclear program continues to generate U.S. opposition, while they are opposed to the program "the Saudis are concerned about a military conflict that could further destabilize the region."

Research for the study was conducted between 2006 and 2009 by the Rand Corp., an independent institute that does much of its work for the Defense Department. In this case, it was produced with financing by the Smith Richardson Foundation.