Around 2,000 protesters blocked car ferries from crossing the Suez Canal after a court ruled that 21 soccer fans would be sentenced to death, witnesses told Reuters.
Protesters reportedly also untied moored speedboats used to supply shipping in a bid to disrupt passing vessels.
Military police recovered five boats and brought them back to shore in Port Said, but two were still drifting, one witness said.
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The Duke and Duchess of Cambridge met young people who have battled mental health issues on Saturday.
Former Chancellor Lord Geoffrey Howe was Margaret Thatcher's longest-serving Cabinet minister, also taking on the role of Foreign Secretary.
Lord Geoffrey Howe is known by many for his resignation speech which was seen as the catalyst which destroyed Margaret Thatcher.