GENEVA U.N. investigators reported on Monday they found it increasingly difficult to interview newly arrived Syrian refugees in Europe and urged countries to allow access to them to help document suspected war crimes.
Their inquiry panel, which says it has a confidential list of suspects on all sides who have committed war crimes or crimes against humanity, called again for major powers to refer Syria to the International Criminal Court.
"We are appealing to countries inside Europe hosting newly arrived Syrian refugees to grant us access and remove any barriers to our work," Paulo Pinheiro, chairman of the U.N. Commission of Inquiry on Syria, told the U.N. Human Rights Council.
He declined to name the countries hampering investigators' access to Syrian refugees. Most have gone to Germany and Sweden while others remain stuck in Greece and Italy seeking asylum.
"Time is of the essence, particularly if the Commission is to continue preparing well-documented reports on the current situation in the country, rather than reports of a historical nature," Pinheiro said.
Vitit Muntarbhorn, a panel member, said it was investigating allegations of chlorine gas being used in the Maqsoud area of Aleppo in April and also of chemical weapons used in August.
It was also looking into alleged use of incendiary weapons - both "phosphorus and napalm" - in the Syrian cities of Hama, Homs and part of Damascus, he told Reuters.
The panel said earlier this month that it had a database of some 5,000 detailed interviews and information, some of which is being shared with European governments seeking to prosecute their nationals fighting as foreign militants in Syria.
"There have been cases of successful prosecution which our information has aided," Pinheiro told the 47-member Geneva forum on Monday without elaboration.
Carla del Ponte, a panel member and former U.N. war crimes prosecutor, said: "We need a formal investigation to be done as soon as possible. Time is passing and we must be ready for a future tribunal. Don't forget, 'no peace without justice'."
"I think it's time that the Security Council is doing something because it is incredible after five years, no justice for the victims," she told reporters.
Syrian President Bashar al-Assad said on Monday that U.S. coalition air strikes which hit Syrian army positions near Deir al-Zor on Saturday were a "flagrant aggression".
Syrian Ambassador Hussam Eddin Aala, addressing the rights council, denounced "this treacherous, deliberate, pre-planned American aggression" that he said had killed dozens of Syrian soldiers and paved the way for an Islamic State attack.
Russia has backed Assad in Syria's five-year civil war while the United States has supported non-Islamist rebel forces fighting to topple him.
(Reporting by Stephanie Nebehay; Editing by Tom Heneghan)