BEIRUT (AFP) - Hezbollah denied involvement on Thursday in a rocket attack on northern Israel as the Lebanese government launched a probe amid heightened fears of a second front opening up in the Gaza war. ""Hezbollah is not aware of the rocket attack,"" Labour Minister Mohammed Fneish told AFP. ""Everyone knows that Hezbollah does not shy away from claiming responsibility for its actions."" Fneish is the sole Hezbollah representative in Lebanon's 30-member national unity government. Prime Minister Fuad Siniora earlier said Lebanon had launched a probe into the rocket attack which, he warned, sought to destabilize the country. ""Lebanon denounces and condemns the firing of rockets and the retaliatory action and believes that such action is in violation of UN Security Council resolution 1701,"" Siniora said in a statement. ""We have asked the competent authorities in cooperation with the UN Interim Force in Lebanon (UNIFIL) to investigate."" He added that Lebanon was committed to the UN-brokered truce that ended the devastating 2006 war between Israel and Hezbollah. Resolution 1701 helped bring an end to that conflict. No one has claimed responsibility for the attack that took place near the village of Tayr Harfa, near the Israeli border. ""Hezbollah has assured us that they remain committed to stability and Resolution 1701 and that is a euphemism for saying they are not involved,"" Information Minister Tarek Mitri told AFP. ""We still hope that Lebanon won't be dragged into this conflict (Gaza) but we have to be more vigilant to make sure that this incident is a one-time incident,"" Mitri said earlier. Two people in northern Israel were lightly wounded by the rockets which drew retaliatory fire by the Israeli army, officials said. Israeli jets also overflew south Lebanon at low altitude, AFP correspondents witnessed. Fneish said the fact that Israel's response to the rocket attack was simultaneous ""raises questions."" ""We are awaiting results of the probe to determine who fired first,"" he said. There have been fears of another front opening up in southern Lebanon since Israel launched the offensive on Gaza on December 27, but Hezbollah chief Hassan Nasrallah has stuck to rhetoric in denouncing the operation. But he warned Israel on Wednesday that all ""possibilities are open."" Thursday's rockets were fired from the same region where security forces found seven missiles directed at Israel in December. Hezbollah at the time also denied any involvement. Officials in Israel and Lebanon said the rockets may have been the work of a Palestinian faction. Ahmed Jibril, the Damascus-based leader of the Popular Front for the Liberation of Palestine-General Command, had threatened on January 3 to open up new military fronts against Israel if the war in Gaza escalates. A spokesman for the party would neither confirm nor deny involvement in Thursday's attack except to slam Israel's offensive in Gaza and inaction by Arab sates. ""This war is open to all possibilities in the absence of a political will from the international community to dissuade Israel from pursuing its Holocaust in Gaza,"" Anwar Raja told AFP. ""Israel and the silent Arab regimes must be conscious of the consequences of their actions."" Representatives of the two main Palestinian factions Hamas and Fatah both denied any involvement. Meanwhile the UN Interim Force in Lebanon (UNIFIL) said it had boosted the number of troops deployed in southern Lebanon in a bid to contain the situation. ""UNIFIL is investigating the circumstances of (Thursday's) incident... and the UNIFIL commander... has called for maximum restraint in order to prevent any escalation of the situation,"" spokeswoman Yasmina Bouziane said. UNIFIL has some 13,000 troops from various countries in southern Lebanon. The force, which was set up in 1978 to monitor the border between Israel and southern Lebanon, was considerably beefed up in the wake of the 2006 war.