Saudi Arabia, growing increasingly nervous about its neighbor across the Persian Gulf, may be hedging its bets and crafting a nuclear back-up plan if a diplomatic deal with Iran fails to halt the Islamic Republic's alleged march toward a weapon. 

The latest sign is a curious visit on Wednesday by Pakistan Prime Minister Nawaz Sharif, the day before Secretary of State John Kerry's visit to the capital Riyadh. 

Sharif arrived in Saudi Arabia following a visit by the Egyptian president on Sunday and Turkey's president on Monday -- but the Pakistan PM's House of Saud call might be the most significant of the three, considering Pakistan is seen by some analysts as Saudi Arabia's future nuclear tech supplier, should the Kingdom take that leap. 

"The visit by the PM ... almost certainly has to be seen in the context of Saudi Arabia looking to Pakistan for nuclear cooperation to counter Iran's emerging status," Simon Henderson, of the Washington Institute, told Fox News. 

Henderson, in an essay for the Washington Institute last month, also noted Riyadh's support for Pakistan's nuclear program, "providing financing in return for a widely assumed understanding that, if needed, Islamabad will transfer technology or even warheads." 

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The developments point to increasing tension in the region over the course of U.S.-driven nuclear talks. Earlier this week, Israeli Prime Minister Benjamin Netanyahu gave an address to Congress urging the Obama administration to pull back on the talks, warning the pending deal is too soft on Iran. 

"When the Israelis and Arabs are on the same page, people should pay attention," Israel's ambassador to the United States Ron Dermer told Fox News on Thursday. "That doesn't happen too often." 

President Obama and his top advisers have urged allies, and lawmakers, to be patient and wait until a deal is actually presented before judging it. 

But some in the region are getting impatient. "Nobody is going to wait for Iran to get a nuclear weapon. Proliferation has already started," retired Col. Derek Harvey, a former senior intelligence official in Iraq, told Fox News. The reported sunset clause allowing unrestricted enrichment for Iran after 10 years may be a driving factor. 

The State Department did not return a request for comment from Fox News on whether it was concerned about Saudi Arabia seeking a nuclear weapon. 

Henderson, in his essay, pointed out that Saudi Arabia and Pakistan may have just renewed a secret nuclear weapons pact. 

In early February, the chairman of Pakistan's Joint Chiefs of Staff Committee visited Saudi Arabia, amid some speculation that the House of Saud had indeed reconfirmed a supposed arrangement with Pakistan for the nation to supply Saudi Arabia with warheads should Iran go nuclear. The visit to Saudi Arabia last month came a day after a successful test-firing of Pakistan's Raad air-launched 220-mile-range cruise missile, which supposedly is able to deliver nuclear and conventional warheads. 

Ironically, the father of Pakistan's nuclear program, Abdul Qadeer "AQ" Khan, also provided the technology to Saudi Arabia's nemesis, Iran. 

Kerry is navigating complicated Arab world geopolitics as he meets with foreign counterparts. Amid wariness over Shiite Iran's nuclear program, these countries are also concerned about Iran's support for Shia militants against ISIS militants in Iraq, support for Houthi rebels in Yemen and the country's ever-growing regional footprint. 

In Riyadh, Kerry met Thursday with counterparts from the Kuwait, UAE, Qatar, Bahrain and Oman -- all Sunni nations concerned about Iran's intentions in Iraq, Syria and Yemen. 

At a press conference Thursday, Saudi Arabia's Foreign Minister Prince Saud al-Faisal expressed concern over Iran's involvement in helping Iraqi forces in Tikrit. "The situation in Tikrit is a prime example of what we are worried about. Iran is taking over the country," he said.   

The Pentagon acknowledged Iran's leading role in the battle for Tikrit. Two-thirds of those taking part in the operation are Iran-backed Shia militias led by Quds Force commander Gen. Major General Qasem Soleimani, the special operations wing of Iran's Revolutionary Guard. 

"This is the most overt conduct of Iranian support in the form of artillery and other things," Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told members of Congress Tuesday. 

Kerry did his best to reassure Saudi Arabia and other Gulf allies that the United States will not ignore Iran's actions in the region outside of the ongoing nuclear talks. 

"The first step is, make sure they don't have a nuclear weapon, but nothing else changes the next day, with respect to our joint commitment, to stand up against any other kind of interference of violation of international law, or support for terrorism," he said Thursday in Riyadh. 

Joining the Sunni alliance against Iran is Israel. Netanyahu cautioned the U.S. on Tuesday not to become too dependent on Iran fighting inside Iraq. 

"When it comes to Iran and ISIS, the enemy of your enemy -- is your enemy," Netanyahu told Congress. 

While Pakistan's prime minister was meeting his ally in Saudi Arabia this week, over in northern Iraq, the head of the Kurdistan Regional Government was also looking to shore up support from one of its patrons -- Iran. 

An official representing the KRG in Iran, Abdullah Akerei, told Iranian Press TV that gas for the Kurdistan region's power plants would be supplied by Iran. 

KRG has welcomed Iran's help in the past. Over the summer, Soleimani and 70 soldiers arrived to defend Irbil from the Islamic State after Mosul fell. Iran has since helped supply the Kurds with weapons to help them in their ongoing fight against ISIS. 

Fox News' Jonathan Wachtel contributed to this report.

Lucas Tomlinson is the Pentagon and State Department producer for Fox News Channel. You can follow him on Twitter: @LucasFoxNews