A UN court investigating the assassination in 2005 of former Lebanese premier, Rafik al-Hariri, has requested evidence from the leader of Hezbollah.
It comes after the head of the militant group suggested Israel carried out the killing.
On Monday Hassan Nasrallah presented what he said were Israeli surveillance videos made before the attack.
The Hezbollah leader, who has predicted that some of his own members will be indicted, said the court should consider Israel’s role.
The UN prosecutor’s office says it has asked the Lebanese authorities to provide all information in Nasrallah’s possession. It has also asked the Hezbollah leader himself to help the investigation.
Hariri died when a lorry bomb struck his motorcade.
Nasrallah said the film he showed had – in his words – been ‘intercepted’ from Israeli planes, which he claimed showed routes frequently travelled by the Lebanese prime minister.
The tribunal near the Hague has yet to indict anyone since opening nearly 18 months ago.