Egyptian security forces in Cairo on Monday dispersed demonstrators protesting Egypt's decision to hand over two Red Sea islands to Saudi Arabia, reported state-owned news outlet al-Ahram.

Riyadh has been a key ally to President Abdel-Fattah el-Sissi since a military coup backed by popular protests ousted Mohammed Morsi, the country's first democratically-elected president, in 2013.

However, el-Sissi's decision to handover the islands' territorial rights to the kingdom drew condemnation, with thousands protesting the move on April 15.

"Protest in Cairo chants anti-Sisi slogans. Protest was almost immediately, violently broken up," human rights activist Iyad El-Baghdadi wrote on Twitter.

Egyptian human rights activist Mona Seif told the Reuters news agency that people waved at protesters from balconies, marking a shift from previous protests.

"There is a different kind of momentum that wasn't there for the past two years," said Seif.

The president's warnings

In a televised address to the nation on Sunday, el-Sissi warned Egyptians against "forces of evil" attempting to destabilize the country.

"I see there are people calling once again for damage to our security and stability ... Our responsibility is to protect security and stability, and I promise Egyptians that no one will terrorize them again," the former military general said.

"I am reiterating to the Egyptian people this is the responsibility of all of us, for us to protect this security and stability," the president added.

Security amiss

Sissi's regime has been characterized by a significant increase in jailed activists and journalists, ranking Egypt at 159 out of 180 countries on Reporters without Borders' 2016 World Press Freedom Index.

The former defense chief rose to power on a platform of bolstering national security in the wake of former president and Muslim Brotherhood leader Morsi's ouster.

In northern Sinai, Egyptian security forces continue to battle militants, most notably Ansar Beit al-Maqdis, which pledged allegiance to the self-styled "Islamic State" militant group.

However, little is known about the Sinai conflict except for uncorroborated statements by Egyptian defense officials due to limited access to the area.

Monday also marked "Sinai Liberation Day," when Israeli forces left the peninsula in 1982, effectively handing full territorial control to Cairo in the wake of the 1979 Egypt-Israel peace treaty.