CAIRO (AP) — Saudi Arabia's king addressed the Egyptian parliament on Sunday, the fourth day of a landmark visit that saw the oil-rich kingdom pledge billions of dollars in investment and aid.

In his six-minute address, King Salman said Egypt and Saudi Arabia have agreed to build a bridge linking the two nations across the Red Sea and to work together to create a pan-Arab defense force, an Egyptian idea first floated last year that was later thought to have been overtaken by Riyadh's creation of a pan-Islamic coalition.

Egyptian lawmakers received Salman with deafening applause and a standing ovation. Some lawmakers waved the kingdom's green flag, while others chanted "all of Egypt greets you" or "welcome!" After the speech, two lawmakers recited poems in praise of the monarch. The king later left the chamber, holding hands with the speaker, Ali Abdel-Al.

That a Saudi king was invited to address the Egyptian parliament is evidence of how close relations are between the two nations, despite differences over policies on Syria and relations with Turkey and Qatar, two Saudi allies accused by Cairo of supporting militant Islamic groups.

Parts of Cairo were locked down during the monarch's visit, with thousands of security forces deployed as Salman and his host, President Abdel-Fattah el-Sissi, travelled across the city of some 18 million people.

Saudi Arabia has been a traditional source of economic and political support to Egypt, but the kingdom significantly stepped up its backing after the military's 2013 ouster of Islamist President Mohammed Morsi.

However, relations shifted when Salman ascended the throne in January 2015 and realigned the kingdom's foreign policy, improving ties with Qatar and Turkey and lobbying the Egyptians to reconcile with them.

Cairo and Riyadh remain divided over Syria, where Saudi Arabia is one of the leading backers of insurgents fighting to overthrow President Bashar Assad. Egypt fears Assad's removal could leave a vacuum that would be filled by Islamists.

The two countries signed 16 agreements and memoranda during Salman's visit, including one that paves the way for the transfer of sovereignty over two strategically located Red Sea islands from Egypt to Saudi Arabia. The Egyptian government says the two uninhabited islands — Tiran and Sanafir at the mouth of the Gulf of Aqaba — are Saudi but have been in Egypt's custody for protection since 1950.

Any agreement on the two islands must be ratified by the Egyptian parliament, a 596-seat chamber packed with el-Sissi supporters. However, news of the agreement has kicked off a storm on social media networks, with activists arguing that handing over the two islands to the Saudis was tantamount to a sell-off to the kingdom.

Many of the critics cited an agreement reached between Egypt and the Ottoman Empire in 1906 that awarded sovereignty over the islands to Egypt. Others posted video clips of nationalist President Gamal Abdel-Nasser, who ruled Egypt in the 1950s and 1960s, asserting Egypt's ownership of Tiran.