UN officials investigating Lebanese leader Rafik Hariri's 2005 assassination have carried out a controlled explosion, but they deny it was a reconstruction of the killing.
The UN tribunal, based near The Hague, carried out the explosion at a military base in south-west France.
Officials said the test was watched by experts who will now examine data yielded by the experiment.
Hariri was killed in a huge truck bombing in Beirut.
That blast killed 22 other people and injured around 230 others.
The Special Tribunal for Lebanon was set up in 2007 to investigate the killing of Rafik Hariri, but has not yet named any suspects.
The tribunal said it had carried out a "controlled explosive experiment" at an air force camp in Captieux, near Bordeaux.
"Neither in its method nor in its purpose can the experiment be compared to a crime reconstruction," the tribunal's statement said.
Officials said the results would be kept confidential.
Rumours that members of the Syrian-backed Lebanese group Hezbollah were among the suspects has added to tensions in Lebanon.
Both Hezbollah and Damascus deny any involvement in the murder, and have denounced the tribunal as politicised.
And in an unexpected U-turn earlier this year, Lebanon's current Prime Minister Saad Hariri - son of the murdered politician - said he believed the investigation had been misled by false testimony.
Saad Hariri also withdrew his own assertion that Syria had been responsible for his father's murder.
Syria dominated Lebanon for nearly 30 years and kept tens of thousands of troops on its soil.
But Hariri's death sparked anti-Syrian protests that led to their withdrawal.
Saad Hariri now rules through a coalition which includes members of Hezbollah.