“The people call for the fall of the regime,” a slogan made familiar during the 2011 uprising in Egypt, rang out in the streets of Cairo on Friday in protests against the government's decision to hand over two Red Sea islands to Saudi Arabia.

The deal, which was signed during a visit by King Salman to Egypt, has angered many Egyptians, who say the uninhabited islands of Sanafir and Tiran belong to Egypt. Saudi and Egyptian officials insist the islands belong to the Saudis, who in 1950 asked Egypt to temporarily protect them.

The main protest against the deal took place near the press syndicate in downtown Cairo, not far from the heart of the 2011 uprising in Tahrir Square.

About 1,500 protesters are currently gathered at the site, according to witnesses and local reports, making this one of the largest protests in Egypt this year. Some reports put the number of protesters as high as 8,000. Police surrounded the area and blocked off routes to the site.

Earlier Friday,  riot police used tear gas to disperse smaller protests across Cairo, but also in Giza and the coastal city of Alexandria. The official state newspaper al-Ahram reported that 25 people were arrested in the Alexandria protests.

On Thursday, Egyptian police  warned against joining the protests, saying in a statement that it would “take all decisive legal measures to maintain security.”

An anonymous Facebook page called “Land is honour” has attracted thousands of supporters, and the hashtag #landfriday is now the top trending topic on Twitter in the Arab world.

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