Chief Palestinian negotiator Saeb Erakat said on Monday Israel should keep the truce on both sides "because the truce is in the interests of both parties to continue".
Sami Abu Zuhri, a spokesman for Hamas, said: "Israel's escalation makes the truce empty. We affirm the right to avenge this crime and to self-defence. We ask the international community to intervene to stop this aggression."
"We think that the past experience of our people with the Israeli occupation confirms that resistance is the main language that this occupation understands," Abu Zuhri said.
Sunday's incident was the second aerial attack in the occupied territory in two weeks, with Israel repeatedly accusing Palestinian President Mahmoud Abbas of failing to crack down on fighters, thus putting serious pressure on the truce.
For his part Abbas, speaking through a translator on ABC television, said: "The climate right now is ready for political negotiations. Hamas should reach that conclusion that now the way is the political way and not any other way."
To which Hamas's Abu Zuhri responded: "This (call) is very strange. We were very surprised about his comments, at a time of continuing [Israeli] aggression against our people and while Fatah is still committed to resistance and they have their armed wing."
Sami Abu Zuhri (R) wants global
intervention to maintain truce
The Palestinian Authority and mainstream Fatah movement condemned Israel for exacerbating the cycle of violence and called for international intervention to support the shaky ceasefire.
"The Israeli government and army is fully responsible for this unjustified military escalation. We ask the international community to intervene to stop ... the situation from deteriorating and to ensure the ceasefire," said Fatah.
The violence has brought calls from Israeli forces for another delay to its August withdrawal from the Gaza Strip after almost four decades of occupation.
An Israeli official has said occupation forces will re-occupy Khan Yunis for what he called "preventive measures", prior to the promised pullback.
"We need to take preventative measures to make the withdrawal possible. One of those measures could see us enter and occupy Khan Yunis to secure the pullout," Giora Eiland, the head of Israel's National Security Council, said.
Palestinian officials and Hamas denounced the threat as pointless.
Hamas's Abu Zuhri said: "This threat is ridiculous and shows how unbalanced Israel is."
Erakat said: "We hope Israel will focus on coordinating the withdrawal with the Palestinian side and to do everything possible to ensure the Gaza withdrawal is peaceful without resorting to threats."
"The Israeli government and army is fully responsible for this unjustified military escalation"
An Israeli military official said Sunday's Israeli aerial operation near Jabaliya in northern Gaza targeted two rocket launchers on the outskirts of the refugee camp.
"The object of the raid was to prevent rocket fire and apart from those two men, who were not hurt in the attack, no one else appeared to be in the area," the Israeli official said.
The two Palestinian victims of the air strike, sisters aged 19 and 32, were in a serious condition, according to medics.
On Sunday, Israeli occupation forces shot a Palestinian civilian seven times in the West Bank city of Hebron, witnesses told Aljazeera.net.
An Israeli spokeswoman said there had been a stabbing incident early on Sunday, without giving any details.
Hebron residents have contested the claim, saying that Umar Sabri Hushia, 28 was a labourer and had no affiliation to any organisation.
Aljazeera.net has learned that a soon to be aired documentary on Israeli TV will show a soldier testifying that Jewish settlers encourage occupation troops to kill Palestinians.
Israeli soldiers shot Hushia seven
times, according to witnesses
In other developments, Israeli Foreign Minister Silvan Shalom told an EU-Mediterranean conference in Luxembourg on Monday that Israeli Prime Minister Ariel Sharon was to meet Abbas soon.
"It might take place in a very short time, in a few weeks," said Shalom.
Luxembourg Foreign Minister Jean Asselborn, whose country holds the EU presidency, speaking at a separate news conference, urged Israel not to destroy the homes of Jewish settlers in the Gaza Strip after the promised pullback.
"Those homes should not be destroyed," but handed to Palestinians "to give them an opportunity to live in dignity", Asselborn said.