An Israeli webcast of the first Eurovision semi-final has been hacked to show faked explosions in host city Tel Aviv.
Viewers saw a warning about a fictitious attack on the city, accompanied by an animated video and the sound of air raid sirens.
The Israeli national broadcaster, Kan, blamed Hamas for the interruption, though the Palestinian militant group has not commented.
The TV broadcast was not affected.
Viewers tuning in to the Kan webcast saw the warning: "Risk of missile attack. Please take shelter," under a fake logo of the Israeli army and the sound of a rocket-warning siren.
Aerial images showed simulated explosions at sites near the Eurovision venue and the warning: "Israel is not safe. You will see."
Kan downplayed the impact of the video, which looped for about 10 minutes.
"We know that at a certain stage there was an attempt, apparently by Hamas, to commandeer our digital broadcast," chief executive, Eldad Koblenz, told Israel's Army Radio.
"But I am happy to say that within a few minutes we managed to assume control over this phenomenon."
On 5 May, the Israeli Defence Forces (IDF) said it had thwarted an "attempted Hamas cyber-offensive" against Israeli targets.
Following the defensive cyber-operation, the IDF added, the Israeli Air Force had carried out an air strike on a building in the Gaza Strip where the Hamas operatives were believed to work.
The incident took place amid an escalation in hostilities between Israel and Hamas that saw militants in Gaza fire almost 700 rockets towards Israel over two days and the IDF carry out air strikes on more than 350 militant targets in Gaza in response. Four Israelis and 25 Palestinians were killed during the escalation.