Dutch officials on Thursday urged nations to boost efforts to create a database of alleged war crimes in Syria, using evidence smuggled abroad by refugees and investigators.
"We already have millions of pages and gigabytes of evidence," Dutch Foreign Minister Bert Koenders told a conference gathering more than 150 experts, diplomats, rights activists and international lawyers.
"And millions more are waiting -- hidden in suitcases and banana crates, buried in caves and pits," he said, voicing the hope that "we can use that evidence to build airtight cases against those guilty of the worst crimes imaginable."
The UN General Assembly agreed in December to set up an investigative mechanism to gather evidence on war crimes in Syria, where the civil war between President Bashar al-Assad's regime and rebels fighting to oust him has raged for six years.
It would be the first step towards trying to prosecute those responsible for atrocities in the war which has left more than 310,000 dead and forced millions to flee as refugees.
The Netherlands, which already hosts top international courts dealing with the world's worst crimes, has offered expertise and a million euros to help get the database up and running.
"After six years of conflict in Syria, the evidence of war crimes, human rights violations and crimes against humanity is overwhelming," Koenders said before the experts met behind closed doors.
"Syrians are taking enormous risks to bring the truth to light," he added, recalling how one military police officer fled the country with flash drives hidden in his socks containing over 28,000 photos of deaths allegedly in government custody.
Another former civil servant escaped with 1,000 pages taped to his body, allegedly containing top-level orders to use indiscriminate violence.
Grassroots investigators smuggled what they said was "proof of war crimes" through a dozen checkpoints hidden in banana crates.
"These brave people know that their actions won't save a single victim" as the crimes had already happened, Koenders said.
"They put themselves in harm's way for a different reason: because they believe that one day justice will prevail."
Koenders said he wanted to see the perpetrators face justice in The Hague -- dubbed the city of peace and international justice -- and urged nations to help fund the investigations.
The database is aimed at furthering the work of the International, Impartial and Independent Mechanism for Syria based in Geneva, which will work under the UN Commissioner for Human Rights.
The mechanism needs some $13 million to fund its the first year of its activities which would involve collecting and analysing any available evidence "that can one day be used to find suspects and bring them to trial."
"For the past six years, international diplomacy has failed the Syrian people," Koenders said, adding however that "a political solution still eludes Syria and accountability is out of reach for now."
Russia, Syria's main ally, and China in 2014 blocked a request by the council that the International Criminal Court begin investigations of war crimes in Syria.
But "if justice is our goal, then we cannot sit back and wait until the war comes to an end," Koenders insisted.