A pickup truck filled with masked militants and homemade rockets blew up in the middle of a Hamas rally, causing mass panic and killing 15 Palestinians and wounding 80 others.
The blast, apparently caused by the mishandling of explosives, triggered a rapidly escalating series of attacks in the worst Gaza violence since Israel pulled out of the region last week.
Hamas blamed the explosion on Israel and launched a volley of homemade rockets at the Israeli town of Sderot, injuring five Israelis, one moderately.
Israel, which denied any involvement in the blast, responded with airstrikes early Saturday on what the army called Hamas weapons facilities. Three people were lightly injured in the strikes, Palestinian health officials said.
The explosion Friday brought a terrified end to one of the last victory rallies by armed militants celebrating Israel's Gaza pullout before an agreement not to publicly parade weapons is to take effect Saturday night, AP reports.
US military analysts are concerned about the appearance of a new Russian sniper rifle known as T-5000