Rome's Colosseum was bathed in red on Saturday as part of a worldwide campaign to highlight the persecution of Christians.

It came as Pope Francis met Asia Bibi's husband and daughter. The Pakistani woman has been on death row for nine years facing spurious charges of blasphemy.

Hundreds gathered outside the iconic Colosseum – a symbol of the martyrdom of early Christians – to hear from Bibi's husband Ashiq Masih who said his wife was innocent of blasphemy. 'This is just hate against Christians, who are considered impure.'

Masih's caughter broke down in tears as she addressed the group, who were earlier received by Pope Francis, who told her: 'I think often of your mother and I pray for her.'

Bibi allegedly made derogatory remarks about Islam after neighbours objected to her drinking water from their glass because she was not Muslim.

'The aim of the blasphemy laws is crush people who believe differently,' Archbishop Nunzio Galantino, secretary-general of the Italian bishops conference, told the gathering.

Human rights groups such as Amnesty International say the blasphemy law is increasingly exploited by religious extremists as well as ordinary Pakistanis to settle personal scores.

The law does not define blasphemy and evidence might not be reproduced in court for fear of committing a fresh offence. There are no penalties for false accusations.

European Parliament President Antonio Tajani, who has been tipped as a possible Italian prime minister after next week's election, said that persecution of Christians was 'a genocide'.

'A message must be sent from this place. It is the duty of Europe to defend these values [of religious liberty] wherever on earth they are trampled on' Tajani said.

Rebecca Bitrus, a Nigerian Christian woman who was held for two years after she was abducted by Boko Haram Islamist militants, told of how she was repeatedly beaten and raped.

During the event, organised by the Catholic group Aid to the Church in Need, there were live link-ups with Aleppo, Syria and Mosul, Iraq, both of whose minority Christian populations have been hit hard by wars.

As well as the Colosseum the Maronite Cathedral of St Elias in Aleppo, Syria, and the Church of St Paul in Mosul, Iraq, were also bathed in red light, symbolising the blood of martyred Christians.

It comes after a campaign in the UK led by Lord Alton of Liverpool led to the Houses of Parliament, Westminster Abbey, Westminster Cathedral and Lambeth Palace as well as dozens of other prominent landmarks being lit red to raise the plight of persecuted Christians.

Lord Alton, a cross-bench peer in the House of Lords and a committed Catholic, previously told Christian Today: 'This will help to wake up governments to the cruel reality of persecution, crimes against humanity and outright genocide so many Christians face in today's world – all of which should make us see red and spur us into action on their behalf.'

John Pontifex, spokesman for Aid to the Church in Need – a Catholic persecution charity behind the initiative – told Christian Today he hoped the worldwide movement 'will shine a light on the blood that has been spilt in acts of persecution and oppression against Christians and others who have lost their lives because of their beliefs'.