LONDON: Hollywood actress Angelina Jolie called on Monday for greater efforts to document and prosecute crimes of rape and sexual violence in war.

The Oscar-winning actress teamed up with former British Foreign Secretary William Hague five years ago to launch a global initiative aimed at ending sexual violence in conflict, tackling impunity and improving support for survivors.

Jolie said she was proud of what had been achieved, but there was still much to do.

"...we are very focused on the next steps: taking the tools that have been developed into the field to help document crimes and support prosecutions, working with militaries to change doctrine and training, and pushing for the implementation of laws to protect the very vulnerable victims," she said in a statement.

The actress, a special envoy of the UN refugee agency, was speaking after an event on the Preventing Sexual Violence in Conflict Initiative (PSVI) at Britain's foreign ministry.

Sexual violence is widespread in war. In Iraq and Syria, Islamic State is accused of sexually enslaving thousands of girls and women, while Boko Haram militants have kidnapped schoolgirls in northern Nigeria. The United Nations has also sounded the alarm over horrific sexual violence in South Sudan.

Jolie and Hague co-hosted the first global summit on ending sexual violence in conflict in London in 2014 and Britain announced on Monday it would host a follow-up meeting in 2019.

It said more than 17,000 military and police personnel had been trained on sexual violence issues since the launch of PSVI.

A key focus this year is tackling the stigma faced by many survivors who are often ostracised from their communities and shunned by their families.

A new version of an international guide for experts working in the field to collect evidence to enable future prosecutions was also launched on Monday, with a focus on interviewing and supporting child and male victims of sexual violence.

Countries the initiative has recently worked in include Myanmar, Colombia, Iraq, Kosovo, Nepal, Nigeria, Rwanda, Somalia, Sri Lanka and Uganda.

Jolie linked up with Hague after her 2011 directorial debut "In the Land of Blood and Honey" set against the backdrop of the 1992-95 Bosnian war in which an estimated 20,000 women were believed to have been raped.