People are being asked to switch off their mobile phones this Sunday to make a stand for victims of war, sexual violence and corruption in the Democratic Republic of Congo.

The 'Your Call' action has been initiated by Woman to Woman, part of Micah Challenge International, to highlight the role women have to play in ending poverty.

The phone fast aims to highlight the connection between the mining of coltan, a valuable metal used in all mobiles, laptops and tablets, and violence against the people of the Democratic Republic of Congo, a country which has large coltan deposits but continues to suffer after years of war.

The DRC is a major producer of coltan, which has become increasingly valuable as the mobile industry explodes around the world.

However, Micah Challenge warns that trade in valuable minerals is tarnished by corruption, with the profits funding violent militia groups that attack girls and women.

The Christian anti-poverty movement says that as much as 80% of the DRC's coltan is being produced illegally and contributing the conflict.

It is concerned about reports that coltan is being smuggled from Congo to neighbouring countries, including Rwanda, Uganda and Burundi, with the revenue then used to fund arms for the opposing militia groups within the DRC.

"We need to speak out about the alarming links between consumer demand for smaller and faster technology, DRC's coltan wealth and widespread violence and rape especially against innocent women," said Amanda Jackson, Head of Policy and Campaigns at Micah Challenge.

Fighting in the DRC over the last 18 years has killed more than five million people. Around a million people have been displaced from their homes, triggering a humanitarian disaster, and nearly a quarter of a million women have been raped or sexually assaulted.

"Despite the horror of the war raging across this part of the world, its victims are largely forgotten, its perpetrators avoid justice and too often, the Church has remained silent when it should speak out. Now it's time for us to take a stand. We should cry for the suffering of women in Congo but we should also protest against it through our activism," Amanda Jackson continued.

The phone fast is being held in conjuction with Raise Hope for Congo, a campaign of the Enough Project, to put pressure on the manufacturers of mobiles and laptops to be more rigorous in ensuring the coltan they use in their products is responsibly sourced.

"If we persuade the technology providers to ensure their products are 'conflict free' it will be a vital step to cutting off money to militia groups which perpetuate violence and the misery of many millions of people across the DRC," said Amanda Jackson.

Micah Challenge wants people to send an email message to major mobile providers asking them to make phones "conflict free".

They are especially looking to the two billion women and girls across the world who own a mobile phone to stand up for the rights of women in the DRC suffering as a result of the conflict and the illegal trade in coltan.

Your Call is being supported by Christians around the world. In the DRC, evangelical leader Joyce Shiuza is encouraging women to take part.

Worship leader Darlene Zschech and Willow Creek's Lynne Hybels have lent their support to Your Call.

"I have been to the Democratic Republic of Congo and seen vulnerable girls and women who are victims of violence and rape. And I have cried," said Hybels.

The Anglican Communion, the Church of Scotland Guild, Girls Brigade International, and EXPOSED anti-corruption campaign are also encouraging people to get involved.

Find out more about how to email major phone providers here