People have gathered at the Roman Catholic church in Sharpeville, and have laid wreaths at the cemetery on the graves of those killed in the massacre as part of Human Rights Day

The Sharpeville Massacre is remembered as one of the bloodiest moments of the liberation struggle, according to the BBC.

Fifty years ago, South African police opened fire on demonstrators in Sharpeville township, 50km (30 miles) south of Johannesburg. At least 180 were injured - many shot in the back as they were trying to flee the scene.

They had gathered outside the police station to protest against pass laws, which required all blacks to carry identity documents - known as pass books - at all times.

No police were ever convicted over the killings.

The Sharpeville massacre led to the banning of the African National Congress (ANC) and its rival liberation movement, the Pan Africanist Congress (PAC), and signalled the start of the underground armed resistance in South Africa.

Today, many in the township are disappointed that the movement they fought for - now the ruling ANC - has failed to improve their lives, our correspondent says.

Many of the shops in Sharpeville have closed down, unemployment persists and there is a sense among some residents that basic public services are inadequate.

"Our lives started changing with Nelson Mandela's release, but people are still financially struggling and finance is still in white people's hands," Abram Mofokeng told Associated Press news agency.

He was 21 when the massacre took place.

In recent weeks the ANC has faced protests from other communities in South Africa, who fear that cronyism and corruption have overshadowed the party's agenda.