Lebanon and Hizbullah will pay a "heavy price," senior IDF officers warned Monday, if the Iranian-funded group fails to learn its lesson from Israel's massive retaliatory strike on Sunday and launches additional attacks against northern Israel. "We hope the message from our response [on Sunday] was understood correctly by the other side [Hizbullah]," Commander of the Galilee Division Brig.-Gen. Gal Hirsch told reporters on Monday as a tense quiet prevailed in the north after rockets flew over both sides of the border on Sunday . "If the message was not internalized and violence recurs, we will know how to retaliate even stronger," he added. "We are ready for another day of fighting if it comes to that." But despite the quiet in the region, the IDF Northern Command continued to maintain a high level of alert on Monday, as the defense establishment expressed fears that Hizbullah might renew its rocket attacks along the northern border. On Sunday, Israel destroyed most of the Hizbullah's military positions along its northern border in the heaviest fighting since the IDF withdrew from southern Lebanon six years ago. Sunday's rocket and artillery exchanges killed two gunmen in Lebanon and wounded two IDF soldiers. The fighting ended after on Sunday afternoon the Lebanese government requested a cease-fire with Israel via the UN. On Monday, senior officers revealed that prior to the Lebanese cease-fire request, Israel had threatened to bomb additional parts of Lebanon, including Beirut, and not just the southern part of the country controlled by the Hizbullah. "We told them that we would expand our firing to other parts of the country," one senior officer explained. "They understood very well what we meant." While some speculated that the Hizbullah attacks were a response to the mysterious assassination of an Islamic Jihad leader in Sidon last week, Lt.-Col. Yishai Efroni, deputy commander of Brigade 300 stationed along the northern border, said he estimated the attacks were meant to coincide with the sixth anniversary of Israel's withdrawal from southern Lebanon. IDF troops, Efroni told The Jerusalem Post Monday, had been on high alert for the past several weeks after anticipating that Hizbullah would launch an attack to commemorate the Israeli withdrawal. "We thought something like this might happen, based on [Hizbullah leader Sheikh Hassan] Nasrallah's continuous threats to kidnap IDF soldiers," Efroni said, adding that internal Lebanese politics concerning Hizbullah's continued control over the southern part of the country has placed immense pressure on the group to preserve its declared title as the guardian of southern Lebanon. Hirsch said Monday that the IDF had been ready for the Hizbullah attack, having prepared a contingency plan. "We were waiting for them for weeks," he said. Hirsch said he had noticed a strong presence of Iranian Revolutionary Guards in southern Lebanon. "Hizbullah is a wing of the Iranian effort to create a frontline against the West," he said, noting that the Iranians train and supply Hizbullah fighters. The IDF would not say if it planned to allow Hizbullah gunmen to return to the outposts along the northern border bombarded on Sunday during the Israeli artillery and missile strikes. Efroni said it was difficult to estimate what Nasrallah was thinking and if he planned to launch additional rocket attacks against Israel. He said that the military has yet to utilize all of the force at its disposal and if Hizbullah made another "mistake" and attacked they would pay dearly.