Egyptian Christians are accusing the government of failing to protect them after an ISIS-claimed attack killed at least 29 and injured at least 20 more.

The shooting happened after a bus convey of Coptic Christians en route to the Saint Samuel monastery near Minya refused to renounce their Christian faith after being halted by Islamist gunmen.

Pope Francis led prayers for those killed in 'another act of ferocious violence', describing those massacred as martyrs.

Speaking to thousands gathered in St Peter's Square, the pontiff said: 'May the Lord welcome these courageous witnesses, these martyrs, in his peace and convert the hearts of the violent ones.'

But relatives of those killed say the attack undermines Egypt's ongoing state of emergency declared after a previous attack in April.

ISIS claimed the attack on Friday – it's fourth since December with more than 100 killed and many more injured.

Egypt's government has previously promised to increase security after separate attacks targeted the country's Christian population.

Kirollos Mahrous, 19, and his 25-year-old cousin Guirguis Mahrous were among the dead as they travelled to a monastery for work.

Another cousin, Eid Fares Ishak, said: 'The state of emergency isn't making anything better, it's as if it's not there.'

He added according to the Guardian: 'The government is supposed to take more precautions and be more firm in case of such attacks, like doing an immediate search following the attack and not waiting for hours like they did.'

Guirguis had tried to join the police force but was turned down because he was a Christian, his friend Mina Adel said.

Talking of the government's response to the attack, he said: '"It's all talk and no action.

'Even this state of emergency: they announced it to calm public opinion, but it's not really helping. Even the priests, bishops and parliament members don't have the same respect from people any more – now no one takes their 'soothing' words seriously. We're fed up. Plus, the government isn't doing anything extra, in fact it's worse than it used to be in terms of how the police treat people.'

The bus was halted by three vehicles and dozens of militants opened fire. Video footage showed the bus raked with bullets.

In response Egypt launched a wave of airstrikes against suspected militant bases in Libya where the perpetrators are thought to have trained. A manhunt for the gunmen is also ongoing in the vast deserts to the west of the site of the attack but no arrests have yet been made.