Sound bombs were tossed by unidentified suspects on Tuesday in Sayeda Zeinab and Zahraa El-Maadi metro stations, causing no casualties, said an interior ministry official.
The official told state news agency MENA that no injuries or damage had been caused.
A state of alert was announced in metro stations on Tuesday in anticipation of protests, according to Ali Fadali, head of the Egyptian Company for Metro Management and Operation.
Dank, a new youth movement, had released a video calling for protests on Tuesday against poverty and worsening living conditions.
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