"If there are no clear answers forthcoming on this issue, I might be forced to recommend to the cabinet early next week the halt of the army deployment in the south," Elias Murr said after a meeting with UN representatives on Saturday.
A stop to the deployment would deeply damage efforts to move in an international force to strengthen the ceasefire.
Israeli commandos raided a Hezbollah stronghold deep inside Lebanon, losing an officer in the clash.
A Lebanese military official told AFP that Israeli helicopters, under cover of mock air raids, landed at dawn two Hummer vehicles in the mountainous region of Afqa, about 30km east of Baalbek, in the central Bekaa valley.
Commandos then drove eastward to the nearby village of Budai where they clashed with Hezbollah fighters, he said.
Meanwhile, the first small contingent of reinforcements for the peacekeeping force - 49 French soldiers - landed on Saturday at the southern Lebanese coastal town of Naqura, with 200 more expected next week.
However, Mark Malloch Brown, the UN deputy secretary-general, said more countries need to step forward to fill out a vanguard of 3,500 troops that the UN wants on the ground by August 28 to help ensure that the truce between Israel and Lebanon holds after 34 days of warfare.
Murr said the Israeli raid could spark Hezbollah retaliation, which in turn could lead to Israeli reprisals. He suggested Israel might be trying to provoke a response, so it could have an excuse to attack the Lebanese army.
The Israeli raid took place deep
inside Lebanese territory
"We will not send the army to be prey in an Israeli trap," he said.
Under the ceasefire terms, Israel has said it will conduct defensive operations if its troops are threatened.
But the raid took place far from positions of Israeli troops in southern Lebanon.
The ceasefire resolution talks about an end to weapons shipments to Hezbollah as part of a long-term end to the conflict - but does not require it under the immediatel truce.
The Israeli military said such operations would continue until "an effective monitoring unit" was in place to prevent Hezbollah from rebuilding its arsenal.
"If the Syrians and Iran continue to arm Hezbollah in violation of the [UN ceasefire] resolution, Israel is entitled to act to defend the principle of the arms embargo," Mark Regev, Israeli foreign ministry spokesman, said.
Hebollah fighters inspect the site
of the Israeli commando raid
"Once the Lebanese army and the international forces are active ... then such Israeli activity will become superfluous."
Such a bold operation, risking the ceasefire, suggested Israel was going after a major target near Baalbek - perhaps to rescue two Israeli soldiers snatched by Hezbollah on July 12, or to try to capture a senior Hezbollah official to trade for the soldiers.