Israel has warned residents of southern Lebanon that it will escalate operations there as it continues its campaign against Hezbollah militants.
Israel carried out about 80 air strikes overnight
In leaflets dropped by Israeli planes, it says its forces will destroy moving vehicles in an area south of the Litani river, 30km (18 miles) from the border.
Israel launched about 80 air strikes against Lebanon overnight. Hezbollah fired more than 140 rockets on Israel.
Diplomats at the UN are discussing a draft resolution to end fighting.
An Arab League delegation is expected to push amendments to the draft, including Lebanon's demand for an immediate Israeli withdrawal.
The current text - drafted by the US and France - calls for an immediate cessation of hostilities and lays the groundwork for a second resolution that would install an international peacekeeping force in southern Lebanon.
Both countries say they are reluctant to see the vote delayed, but want to discuss Arab amendments.
Russia's UN ambassador said Moscow would not agree to any resolution which did not have Lebanese approval.
"It is obvious for us that the draft, which is unacceptable to the Lebanese side, should not be passed because it will only prolong the conflict and violence," Vitaly Churkin said.
The UN Security Council is not expected to vote on the draft resolution until Wednesday.
Senior Israeli officials have said they are broadly happy with the resolution's text.
Leaflets dropped in Tyre, the biggest Lebanese city south of the Litani river, said operations against what they described as terrorist elements would be escalated with extreme force.
Any vehicles of any sort moving on the road south of the Litani, they say, will now be attacked on suspicion of carrying rockets, material or terrorists.
The BBC's Jim Muir in Tyre says there is hardly any traffic in the city, where road links to the outside have been cut.
It is going to be hard for anyone wanting to escape to get out and equally hard for relief agencies to get supplies in, he says.
UN officials have warned of a deteriorating humanitarian situation in Lebanon, as aid agencies face problems with access to parts of the region.
Israeli Foreign Ministry spokesman Mark Regev told the BBC Israel was trying to co-ordinate aid efforts with the international community but could not assume every lorry was carrying aid rather than weapons.
It is not clear whether the Israeli warning was linked to a plan to extend ground operations to the Litani.
Israeli Defence Minster Amir Peretz said Israel was preparing to occupy more areas of southern Lebanon from which Hezbollah rockets are being fired.
The BBC's Jeremy Bowen in Lebanon says Israel may be using threats to step up military action as a means of putting more pressure on the Lebanese government.
In other developments:
- The Israeli authorities say they are mounting an operation to temporarily remove all the remaining residents of the city of Kiryat Shmona - hit by more Hezbollah missiles than any other town in Israel - in what they describe as a four-day holiday paid for by the state.
- Reports say at least 15 people were killed when a predominantly Shia area of Beirut was hit late on Monday
- An Israeli soldier dies and five are wounded in clashes with Hezbollah in southern Lebanon, the Israeli military said
- UK Prime Minister Tony Blair says he hopes that an agreement will be reached on Wednesday to end the fighting between Israel and Hezbollah
Lebanon has told army reservists to report for duty after the cabinet decided to send 15,000 soldiers to the southern border area once the Israelis pull out.
Cabinet ministers who are members of Hezbollah or loyal to the group have given their backing to the government plan.
Israeli Prime Minister Ehud Olmert described the plan as an "interesting step" and said his government would study it.
He told a news conference that such a move had to be accompanied by the disarming of Hezbollah guerrillas.
"The faster we leave south Lebanon, the happier we will be, especially if we have achieved our goals," he said.
More than 900 Lebanese, most of them civilians, have been killed in the conflict, the Lebanese government said. More than 90 Israelis, most of them soldiers, have also been killed.