Burkina Faso's opposition staged the country's biggest demonstration in decades on Saturday to protest against an attempt by President Blaise Compaore's party to abolish constitutional term limits.
The peaceful march, which was joined by dissidents from the ruling Congress for Democracy and Progress, steps up pressure on Compaore, who took power in a coup in 1987 and won an election in 2010 to secure his second and final elected five-year term under a constitution that dates from 2000. Opposition leaders say those polls were rigged.
A gradual deepening of democracy has contributed to increased stability and growth in some African countries, but Burkina Faso is one of a number of nations dominated by a leader of several decades' standing.
It remains impoverished despite emerging as a significant gold producer, and has been an ally for Western governments concerned about the rise of militant Islamist groups in the region.
Opposition leaders said between 300,000 and 500,000 people joined the march through the capital. There was no official estimate but witnesses said it was the largest in living memory.
"We are waiting for President Blaise Compaore to become aware of what the people are demanding today, namely the abandonment of his project to revise Article 37 of the constitution," opposition leader Zephirin Diabre told journalists.
"If Blaise Compaore doesn't hear us, we will continue to march," he said.
Dozens of ruling party members have resigned in recent weeks because of the drive to amend the constitution and also to establish a Senate, which the opposition says would be too costly.
Many of the dissidents had fallen out of favor since a ruling party congress in 2012.
"Increasingly, people in Burkina Faso realize that we need to change policy," said Roch Kabore, the former president of the National Assembly.