CAIRO - US Secretary of State John Kerry sought to assure Middle East allies Sunday that the Iran nuclear deal would make them safer, as he began a regional tour in Egypt.

Kerry met his counterpart Sameh Shoukry to patch up troubled relations between the two countries with a pledge of support. He later met President Abdel Fattah al-Sisi, and was also scheduled to fly to Qatar to meet Gulf Arab counterparts.

Egypt and other regional states such as Saudi Arabia are suspicious of Iran, which they see as bent on destabilising them. "There can be absolutely no question that if the Vienna plan is fully implemented, it will make Egypt and all the countries of this region safer than they otherwise would be or were," Kerry told a joint news conference with Shoukry.

"The United States and Egypt recognise that Iran is engaged in destabilising activities in the region -- and that is why it is so important to ensure that Iran's nuclear programme remains wholly peaceful," he said. "If Iran is destabilising, it is far, far better to have an Iran that doesn't have a nuclear weapon than one that does."

Ties between the US and Egypt had frayed after then army chief Sisi overthrew Islamist president Mohamed Morsi in 2013. More than 1,000 of Morsi's supporters were killed in a sweeping crackdown on protests, and militants have since killed hundreds of soldiers and policemen. Most of the attacks have been by the Egyptian affiliate of the jihadist Islamic State group, which a US-led coalition is battling in Syria and Iraq.

Kerry spoke of the need for a "balance" between fighting militants and respecting human rights in Egypt. The "US and Egypt are moving back to a stronger base of relationship", he said at the news conference. "There has been a little bit of tensions here and there over certain issues. The US has expressed concerns about some of the challenges of human rights protection."

Washington froze arms deliveries to Cairo following the crackdown on Morsi's supporters, but resumed full aid in March and delivered a batch of F-16 jets last week. "We have signficantly increased military cooperation as seen from the delivery of the F-16s, other equipment and goods which are very essential in the fight against terrorism," Kerry said. Earlier, at the televised start of the meeting with Shoukry, Kerry said Washington wanted to support Cairo economically and politically.

"The American people are committed to the security and economic wellbeing of the Egyptian people," he said. The United States has again grown supportive of Egypt, long a key Middle East ally, as Sisi battles the IS insurgency in the Sinai Peninsula.

"One of the key decision points of why we decided to move forward was our estimate that the Egyptians were facing a very serious threat from ISIL-affiliated organisations in the Sinai and that we needed to help them," a State Department official said ahead of Kerry's visit, using another acronym for IS.

However, Washington has remained critical of Egypt's human rights record. On Sunday, when asked about jailed journalists, Shoukry said: "None of these journalists are held in relation with their profession as journalists" but because of their "implication in terrorist activities". Kerry's trip, which ends on August 8, will not include Israel, one of Washington's closest allies, which has been a fierce critic of the July 14 nuclear deal between the world powers and Iran.

In Doha, Kerry will meet his counterparts from the six Gulf Cooperation Council member states, seeking to allay their fears about Shiite Iran, following the nuclear deal signed in Vienna. "This is an opportunity, really, for the secretary to do a deep dive with the GCC foreign ministers to try to respond to any remaining questions that they might have and hopefully to satisfy them and ensure that they're supporting our effort going forward," the State Department official said. Many Gulf Arab states have said they are concerned about Iran's regional ambitions following the pact with the United States and Britain, China, France, Germany and Russia.