Police have dispersed hundreds of anti-hunger campaigners in Nigeria's capital, Abuja, for littering the city.
The march, organised by Action Aid, was intended to raise awareness about widespread hunger in Africa's most populous nation.
The marchers were blocked by the city's environmental protection officials, who complained about the litter from discarded polythene bags.
The police were called in when the marchers ignored the officials.
The officials also complained about the loud music played by the campaigners, says the BBC's Chris Ewokor, who joined the march.
Despite the country's massive oil wealth, one in three of Nigeria's 140 million people goes to bed hungry, Action Aid says.
"Their hunger is an indictment of those who have more than enough to eat in a country with more than enough resources and potential to banish the hunger it breeds," organisers of the march said.
The marchers had intended to present petitions to President Umaru Yar'Adua and parliamentarians to encourage policies to end hunger in the country.