Mofaz spoke just hours after Israeli fighter jets attacked a command post of resistance group Hizb Allah in south Lebanon and army bulldozers entered Lebanon to demolish a Hizb Allah post just north of the community of Ghajar.
The Israeli military and Hizb Allah both denied an Israel Radio report that warplanes struck for a second time at midday on Tuesday, the resistance group saying an explosion heard in the area was caused by a previously unexploded artillery shell.
Monday's attack on Hizb Allah targets "was the largest-scale, most hostile since the departure of Israeli forces from Lebanon [in 2000]", Mofaz said in remarks broadcast on Israel Radio.
He added that the Israeli response "was the widest against attempts by Hizb Allah to escalate the situation".
Tuesday's air raid "targeted a position used by Hizb Allah to fire rockets and mortar shells at the north of Israel", an Israeli military spokesman said without giving further details.
On Monday, Hizb Allah mortars and rockets slammed into Israeli army outposts, and Israel's warplanes and shells hit the resistance group's targets in a sharp escalation of violence.
Aljazeera learned that four Hizb Allah activists were killed and 11 Israeli soldiers wounded in the fighting which raged through the night and involved at least eight Israeli helicopter attacks on Hizb Allah targets.
The shelling also damaged a house in an Israeli border community and sent thousands of Israeli civilians into bomb shelters.
Hizb Allah has acknowledged three of its fighters were killed and its Al-Manar TV station has said a fourth died of battle injuries.
The Israeli army said there were several casualties among soldiers in the border exchange, but would not give details.
Al-Manar television and other Lebanese stations said one Israeli soldier was killed and seven wounded in Hizb Allah fire and that two Israeli tanks were destroyed.
Israel's military said the border
clash led to several casualties
Lebanese Prime Minister Fuad Siniora spoke with the leadership of Hizb Allah and the American, French and Russian ambassadors in an attempt to defuse the tensions in southern Lebanon.
Abbas Nasir, Aljazeera's correspondent in Lebanon, said Siniora's conversations with Western ambassadors and the UN envoy appeared to be part of an attempt to contain the crisis and prevent further escalation.
Siniora may also be seeking to safeguard Lebanon against any damaging fallout at the UN and other international forums.
Lebanon has requested that the UN peacekeeping force stationed in the country, Unifil, appeasl to Israel to persuade it not to further retaliate for the Hizb Allah strikes, Israel Army Radio said.
Witnesses in southern Lebanon said heavy exchanges lasted
for two hours in the evening and continued intermittently into the night as Hizb Allah fighters fired truck-mounted rockets at Israeli army positions.
The fighting marked a sudden upswing in violence, the first cross-border fighting in five months.
Hizb Allah fighters blamed Israel, but Israel said Hizb Allah attacked first and with the backing of supporters in Syria and Iran.
Hizb Allah frequently targets Israeli troops in the Shebaa Farms area, which the Iranian-backed group says should have been returned by Israel when it withdrew from south Lebanon.
The Shebaa Farms has been the
scene of many border clashes
Israel says it captured the area from Syria in 1967 and will discuss its control of the land only in any future peace talks with Damascus.
The US, which considers Hizb Allah a "terrorist" organisation, condemned the rocket attacks, accused the group of provoking the fighting, and urged the Lebanese government to take charge of the area.
But it also urged Israel to exercise restraint in its response.
Hizb Allah, which controls the Lebanese side of the border with Israel, is an ally of Syria in Lebanon. In recent weeks it has stepped up its criticism of the UN and its investigation into the killing of former Lebanese prime minister Rafiq al-Hariri.
Israel hinted on Monday that it was prepared for additional retaliation.
"Israel will do all possible to protect its residents in the north," Mofaz said.
Syria, Iran blamed
He blamed Syria and Iran for the attacks, saying they were designed to ease international pressure on Damascus.
"Behind the fire in the north stand also Syrian and Iranian interests to ignite the northern border and turn the attention from Syria, which today is under heavy international pressure," Mofaz said.
Hizb Allah has been disturbed about political change in Lebanon after the April withdrawal of the Syrian army in the wake of international and domestic outrage over al-Hariri's assassination.
The group, which led the guerrilla war against Israel's 1982-2000 occupation of part of southern Lebanon, is under international pressure to disarm under a 2004 UN Security Council resolution that demanded that all militias in Lebanon give up their weapons.
Hizb Allah has refused to lay down its arms under that resolution.