US Republican mega-donor and hard-line Zionist Sheldon Adelson has not decided yet�which presidential candidate supports Israel the most and deserves his financial backing in election.

The casino owner, who together with his wife spent nearly $100 million in the 2012 presidential campaign cycle, is still weighing his options, according to more than half a dozen�sources close to Adelson,�The Hillreported on Sunday.

Adelson has expressed interest in Florida Senator�Marco Rubio and his wife Miriam likes Texas Senator�Ted Cruz, the sources say.

�The guy is cagey,� said a conservative leader with ties into the donor community who spoke with Adelson recently. �He said �I like Rubio,� he did not say �I support him�� But he also said that his spouse feels more strongly about Cruz.

"At the end of the day, he wants somebody he can agree with on the issues,� said a source who speaks to Adelson regularly. �But winning is the most important criteria.�

He has�also met several times�with Jeb Bush's campaign�and has been reassured that the former Florida governor will staunchly�defend�Israel, the subject the billionaire cares about most.

Adelson was listed by Forbes in June as having a fortune of $28 billion, making him the 18th richest person in the world.

He is a major contributor to Republican Party candidates, which has resulted in his gaining significant influence within the party.

Adelson, a Zionist Jew, has said his most important issue when considering which candidates to support in US elections is "the safety of Israel."

Adelson donated $1 million to a political action committee supporting Newt Gingrich, who was a Republican candidate for the presidential nomination in 2012.

Funded almost entirely by Adelson, the former speaker of the House of Representatives assaulted and�nearly destroyed the ultimate GOP nominee, Mitt Romney.

Many conservatives believe the negative ads by Gingrich contributed to Romney�s loss to the incumbent candidate, President Barack Obama.

By Press TV