One person was killed and 50 people were injured in clashes on Sunday as security forces tried to evict squatters from a Nile island, the government and witnesses said.
The incident on Warraq island in Cairo came amid a government campaign to remove encroachments from state property and land, an interior ministry statement said.
A health ministry statement said one man was killed and 19 people were injured, and the interior ministry said 31 policemen were hurt in the clashes.
A large force that had headed to the island was met by "some of the encroachers who gathered to protest against the implementation of the removal orders," the interior ministry said.
It said protesters fired birdshot and threw stones at officers, prompting police to use tear gas to disperse them.
Witnesses including a former head of the island's municipality told AFP they had not received advance warning about the move.
In May, President Abdel Fattah al-Sisi ordered a campaign to recover state-owned land which had been encroached upon.
The authorities announced in June that the government had retaken control of more than 919.4 thousand feddans, or around 386,150 hectares (95,390 acres).
© 2017 AFP