The U.S.-Israel Enhanced Security Cooperation Act will be signed Friday on the eve of Republican rival Mitt Romney´s visit to Israel • U.S. also announces readiness of largest ever bunker busting missile and agreement with Lockheed Martin for new Israeli version of the F- 35 stealth fighter jets.

President Barack Obama will give a boost to U.S.-Israeli military cooperation on Friday when he signs a bill that calls for enhanced collaboration with Israel on missile defense and intelligence, as well as increased access to advanced U.S. weapons.

Obama will seek to show American Jewish voters his commitment to Israel´s security by signing the bill at a White House ceremony, which appeared timed to upstage his Republican presidential challenger, Mitt Romney, on the eve of the latter´s visit to Israel.

The new bill, named the U.S.-Israel Enhanced Security Cooperation Act, was passed with broad support from Democrats and Republicans last week. It will be signed a day after the U.S. announced that its largest bunker-buster missile, capable of penetrating underground facilities, is operational and ready for use if needed. Known as the Massive Ordnance Penetrator (MOP), the 30,000-pound bomb — which contains over 5,000 pounds of explosives — was originally designed to take out hardened fortifications in Iran and North Korea.

The announcement that it is operational comes at a time when the Western world is increasingly concerned over the potential transfer of Syria’s chemical weapons, particularly to Hezbollah and other terrorist groups. The announcement may also be of special concern for an Iranian regime trying to protect its nuclear installations by building them deep underground.

“If it needed to go today, we would be ready to do that,” United States Air Force Secretary Michael Donley told the Air Force Times this week. “We continue to do testing on the bomb to refine its capabilities, and that is ongoing. We also have the capability to go with existing configuration today,” said Donley.

The Pentagon, meanwhile, has reached an agreement with Lockheed Martin Corp. on a $450 million program to enhance electronic warfare equipment on the F-35 fighter jet, and integrate Israeli-unique systems beginning in 2016, according to sources familiar with the negotiations. The deal comes as Defense Secretary Leon Panetta prepares to visit Israel next week where he will discuss heightened tensions with Iran.

The deal, to be finalized in the coming weeks, marks a big step forward for Israel´s $2.75 billion agreement to buy 19 F-35 jets, which was signed in October 2010 and includes options for up to 75 of the radar-evading fighters.

When it first approved the sale in September 2008, the Pentagon said the Israeli arms sale could be worth up to $15.2 billion if all options are exercised.

"This agreement kicks off the Israeli program," said one of the sources, who was not authorized to speak on the record. "Now all of the agreements are in place."

The deal will allow increased participation in the F-35 Joint Strike Fighter program by Israeli companies, including Elbit Systems Ltd and state-owned Israel Aerospace Industries, which will start building wings for the radar-evading warplane.

IAI already builds wings for the F-16 fighter jet, the world´s most widely used fighter, also built by Lockheed. Elbit, in a joint venture with Rockwell Collins, makes the advanced helmet used by pilots on the single-seat F-35.

As part of the agreement on the development of the new Israeli version of the F-35, Israel will be able to install its own radio and data-link systems, as well as other equipment, on the jets it is buying.

But the deal also covers enhancements to the airplane´s electronic warfare capabilities that will benefit the United States, Israel and nine other countries that either have already ordered fighter planes, or plan to in the coming years.

Congress passed the U.S.-Israel Enhanced Security Cooperation Act with broad support from Obama´s Democrats and Republicans last week.

"The bill deepens our security cooperation with Israel by expanding our military assistance and providing Israel with access to additional equipment," White House spokesman Tommy Vietor said on Thursday.

Obama, criticized by some of Israel´s U.S. supporters for being too tough on a close ally, wants to shore up his support among Jewish voters, who could prove critical in battleground states like Florida and Pennsylvania in the November 6 election.

Obama received 78 percent of the Jewish vote in the 2008 election, but a nationwide Gallup poll in June showed him down to 64% with support for Romney at 29%.

Romney hopes his trip to Israel will resonate with Jewish voters at home. He will arrive there from London on Saturday and will meet Israeli Prime Minister Benjamin Netanyahu, who has had a strained relationship with Obama.