An al-Aqsa Martyrs Brigades leader says the Palestinian militant group will no longer respect a six-month truce after Israeli raids killed three militants.
"There will be no limits to our responses... We need to protect our people," said Zakaria Zubeidi.
Mr Zubeidi speaks for the group only in Jenin, where one of its commanders was killed during an overnight raid.
Meanwhile Palestinians in the West Bank are voting in local polls - the first since Israel's pullout from Gaza.
Samer Saadi, a local leader of the al-Aqsa Martyrs' Brigades, was shot dead during what Israeli forces called an arrest raid in Jenin.
"This Zionist enemy only understands the language of bullets. We in the al-Aqsa Brigades have committed ourselves to the truce but this enemy is not committing to the truce," Mr Zubeidi told reporters.
The deaths come in an upsurge of violence since Israel completed its withdrawal from the Gaza Strip on 12 September.
Oh, well, that was a surprise, eh? I mean, how long did it take for the Palestinians to start firing rockets (29 of them) from the Gaza Strip? A couple of days?
According to the Israeli army, Saadi was killed as he fired at soldiers, while the two other men killed in a separate incident had assault rifles and were about to do the same.
Well, will you look at that? The eeeeeeevil Israelis didn't even have the decency to let the two guys shoot first. I mean, the Israelis have the military advantage; they should at least let the poor oppressed Palestinians have the first pop.
And now, apparently, the militants are using knives! What's next—pointed sticks?
The Israeli army has shot and wounded a Palestinian teenager after he attempted to stab soldiers at a West Bank checkpoint near Nablus.
The teenager ran towards the soldiers brandishing a knife and shouting "God is great", witnesses said.
Israeli soldiers fired at the youth, lightly wounding him, said witnesses.
Hahahahahahaha! Excellent! So the little twerp doesn't get to be a martyr, he just gets to break rocks (for the rest of his natural, I sincerely hope).
"We will continue martyrdom operations throughout Palestine until the occupation leaves. The barriers of shame and disgrace set up by the Zionists shall face more blows," said al-Aqsa Martyrs Brigades in a statement on their website.
So, now that they are out of the Gaza Strip, what would be occupied territory, I wonder? Could it be the whole of Israel?
Seriously, can people stop whining about Palestinian right, please? Has it ever occured that, just maybe, if the Palestinians stopped trying to kill Israelis, that they might be allowed free movement throughout the area? That the wall might come down? Or has it even occured to these idiots that compromise is a two-way thing? Of course, they aren't interested in compromise; it's the destruction of Israel or nothing.
If I was ruling the world, I would be tempted to broadcast to both the Palestinian Authority and Israel, saying, "Right, if one more person gets killed, we're going to nuke to both of you." It's so frustrating!