WASHINGTON: A senior administration official says President Barack Obama is authorizing an additional $70 million in military assistance to Israel.    

The official says the funds will go to help Israel expand production of a short-range rocket defense system. The system, called Iron Dome, helps Israel defend itself against rocket attacks.

Obama is to announce the additional funds when he signs a bill at the White House expanding US military and civilian cooperation with Israel.

The announcements are an attempt to upstage Republican rival Mitt Romney on Israel ahead of the presumptive Republican nominee's trip there this weekend and meeting with Prime Minister Benjamin Netanyahu.

The official spoke on the condition of anonymity because the official was not authorized to speak ahead of the president's announcement.