LISBON, Portugal — Thousands of people have marched through downtown Lisbon in a peaceful anti-NATO protest during a summit of the alliance's leaders in the Portuguese capital.
The protestors chanted anti-NATO slogans, held banners and banged drums as they passed down the city's main avenue.
Many of them belonged to Portuguese trade unions and local left-of-center political parties.
Armed riot police kept a close watch on the march Saturday as authorities braced for possible violence. Some shops boarded up their windows.
Police detained about 20 protestors near the cordoned-off summit site after they sat in the road and blocked local traffic.