Hamas vows to avenge Gaza attack
Gaza Strip: Hamas on Thursday said "all options are open" to avenge the Israeli strike on Gaza that killed at least 20 Palestinians.
Five children and a cameraman were among those killed during the clashes with Israeli troops on Wednesday.
In a statement published on the internet, Hamas called on its fighters to attack Israel "in every place and with all means available".
"This enemy only understands the language of force," it said.
Israel blames Hamas for the violence. Israeli Prime Minister Ehud Olmert said in an interview with Israel's Maariv newspaper that Hamas was "responsible" and would pay the price.