CAIRO: Egypt has detained 39 people, including a US citizen, accused of torching a tram during a protest against the overthrow of President Muhammad Mursi, judicial sources said Saturday.

The accused, who were placed in 15-day preventive detention, were members of Mursi’s Muslim Brotherhood movement, the sources said, adding that they were also accused of rioting and attacking policemen on Friday during protests in Cairo.

On Friday the Interior Ministry said students linked to the Muslim Brotherhood had torched a tram carriage in Cairo’s eastern district of Heliopolis.

Sources said Saturday that one of the detainees had a US passport, but it was unclear if he held other citizenship.

On Friday, a young boy and a man were killed as supporters and opponents of Mursi clashed in several parts of Egypt, including in Cairo, officials said.

The confrontations came as pro-Mursi groups called for a week of anti-military protests under the slogan “Massacre of the Century” — a reference to the violent dispersal of two pro-Mursi protest camps on Aug. 14 in which hundreds of people, mainly Mursi supporters, were killed.

Authorities have launched a sweeping crackdown on former rulers in recent months, arresting some 2,000 people, including most of the top leadership of the Muslim Brotherhood, the country’s oldest and most well-organized movement.

Mursi, Egypt’s first freely elected president, is himself in custody on charges of inciting violence during clashes outside the presidential palace in December 2012.

Meanwhile, Egypt’s Interior Minister said his forces have foiled several attempted terror attacks and arrested leading militants, accusing the Muslim Brotherhood of mobilizing and financing some of the country’s most violent groups to cause unrest.