U.S. Secretary of State John Kerry will head to the Gulf in August seeking to allay fears over the Iran nuclear deal, as Saudi Arabia Thursday warned Tehran against any further "mischief" in the region.

Back at work only days after an 18-day negotiating marathon to seal the unprecedented accord, Kerry met Saudi Foreign Minister Adel al-Jubeir, the beginning of a charm offensive designed to win over the many doubters in the United States and abroad.

Saudi Foreign Minister Adel al-Jubeir warned Iran Thursday to use the economic benefits of a new nuclear deal to help its people and not fund "adventures in the region."

"If Iran should try to cause mischief in the region we're committed to confront it resolutely," Jubeir said after meeting U.S. Secretary of State John Kerry, days after the landmark deal was struck granting Tehran sanctions relief in return for dismantling and mothballing most of its nuclear program.

A car bomb exploded Thursday night at a security checkpoint in the Saudi capital Riyadh, killing the driver and wounding two policemen, the interior ministry said.

The blast came with the kingdom on alert for attacks by the Islamic State group of jihadists, who have been blamed for killing policemen and for slaughtering members of the minority Shiite community.

U.S. President Barack Obama and Saudi Arabia's King Salman on Tuesday discussed the "urgent" need to end fighting in Yemen, hours after Saudi-backed loyalists retook control of Aden airport.

After discussion about a recently inked nuclear deal with Iran, the White House said Obama and Salman "also spoke about the urgency of stopping the fighting in Yemen and the importance of ensuring that assistance can reach Yemenis on all sides of the conflict."

Forces loyal to Yemen's exiled president, backed by Saudi-led air and naval support, recaptured the airport in second city Aden Tuesday after a four-month battle with Iran-backed rebels, military sources said.

Fighting in the port city escalated as U.N. chief Ban Ki-Moon expressed disappointment that a U.N.-declared ceasefire failed to take hold over the weekend.

Saudi police shot dead a wanted man on Tuesday during an exchange of fire, in which he killed his father and wounded two policemen, official media said, providing few details.

The shootout comes with the kingdom on alert for attacks by the Islamic State jihadist group.

Iran and major powers headed into another late night of talks Monday on a deal to rein in Tehran's nuclear ambitions, as negotiators struggled to overcome the remaining few obstacles.

The White House said the marathon discussions in Vienna had "made genuine progress" but suggested they would stretch beyond a Monday night deadline.

Saudi Arabia's King Salman on Monday named a new housing minister and replaced the head of the royal court in his latest government shuffle.

A decree named Minister of State Khalid bin Abdulrahman al-Issa to replace Hamad bin Abdulaziz al-Suwailem as head of the royal court, a type of gatekeeper to the king.

Residents of the Saudi Red Sea city of Jeddah are slowly returning to its historic centre, where a Ramadan cultural festival and UN heritage status are giving new life to the old quarter.

Last year the United Nations added Jeddah to its UNESCO global heritage list, acknowledging its distinctive architecture, which evolved from the city's centuries-old role as a global trading hub and the gateway for pilgrims visiting Islam's holiest sites.

Head of the Mustaqbal bloc MP Fouad Saniora and Interior Minister Nouhad al-Mashnouq returned to Lebanon from a trip to Saudi Arabia where they held talks on the latest local developments with Mustaqbal Movement chief MP Saad Hariri, reported al-Joumhouria newspaper on Saturday.

Informed sources told the daily: “The officials agreed on measures to confront these developments and prevent the escalation of the government crisis.”