"We cannot blame any Palestinian faction and we don\'t know who fired the rockets," Hamas spokesman in Lebanon, Raafat Morra, told AFP.
"Hamas is pursuing its combat inside Palestine and our principle is not to use any other Arab soil to respond to the occupation. This is our firm policy," he said.
"Basically what is happening is the fault of Israel because it is impossible to contain the Arab and Islamic world after the Gaza massacre."
Lebanon, Israel trade fire: reports
Earlier, the Israeli army has fired into northern Lebanon after several rockets were fired at the Jewish state, an army spokeswoman said.
"We carried out direct fire at the source of the rocket fire from Lebanon," she said.
The army fired five shells, a military source said without clarifying the type of ordnance used.
Several rockets fired from Lebanon hit northern Israel, slightly wounding two people on Thursday.
"Three rockets landed in Israel fired from Lebanon," said police spokesman Micky Rosenfeld.
Two people were slightly wounded, he said, adding that police sappers and bomb disposal units were working on the scene.
The rockets fell around the area of the northern town of Nahariya, where residents were called to stay inside their homes, Israeli media reported.
The rockets fell a day after the chief of Lebanon\'s Hezbollah warned that "all possibilities" were open against Israel amid its deadly offensive in Gaza.
Israel and Hezbollah militia fought a 34-day war in 2006, after guerrillas from the Lebanese Shi\'ite movement seized two Israeli soldiers in a deadly cross-border raid.
During the conflict, Hezbollah sent more than 4,000 rockets into northern Israel.
The war killed more than 1,200 Lebanese, mostly civilians, and more than 160 Israelis, mostly soldiers.
Israel is currently in the 13th day of a massive offensive in the Gaza Strip.
Hezbollah carried out its deadly raid in 2006 two weeks into Israel\'s last major operation in Gaza, launched after Gaza militants seized another Israeli soldier in a raid near the Palestinian territory.
Hezbollah\'s warns Israel
In his address on Wednesday, Nasrallah said: "We have to act as though all possibilities are real and open (against Israel) and we must always be ready for any eventuality."
His comment marked the first time he has spoken so openly on the possibility of a renewed conflict with Israel since the war in Gaza began on December 27.
Nasrallah, addressing tens of thousands of supporters via video link at his stronghold in Beirut\'s suburbs on the occasion of Ashura, said that the 2006 conflict would be nothing compared to what awaits Israel if it opens a second front.
"I say to (Israeli Prime Minister Ehud) Olmert, the loser, the vanquished in Lebanon that \'you cannot overcome Hamas or Hezbollah\'," Nasrallah said. "Your 2006 war will be but a walk in the park compared to what we have prepared for you in the event of a new offensive.
"We are ready to sacrifice our souls, our brothers and sisters, our children, our loved ones for what we believe in," said Nasrallah, whose Shi\'ite militant party is backed by Syria and Iran. "We will not abandon the fight or our weapons."