Hezbollah's representative in Iran ruled out the disarmament of the group's militia on Monday.
Abdullah Safieddin said the movement would buy new weapons if necessary, despite the fact UN resolution 1701 demands the disarmament of all armed groups in Lebanon and prohibits any sales or supply of arms and related materiel to Lebanon except as authorised by its government.
"If anybody wants to resist, they will seek to buy arms if need be," he told the Shargh newspaper.
"Hezbollah will remain as it is. We even believe this war made the spirit of resistance more serious. We will do our political work but we will defend our country too."
For their part, Israel ruled out any peace talks with Syria as long as it continues to support "terrorism".
The prime minister, Ehud Olmert, on a tour in northern Israel said via his spokeswoman that it should not be forgotten that the rockets fired by Hezbollah at Israel during the month-long Lebanon offensive came from Syria.
Peace talks between Israel and Syria have stalled for more than six years.
Syria has repeatedly demanded the return of the Golan Heights, the strategic plateau which Israel occupied in the 1967 Middle East war and annexed in 1981.
Earlier, Avi Dichter, the public security minister, said Israel should resume negotiations with Syria and, in exchange for peace, give up the Golan Heights.
"We are at the tilting edge still. This can easily start sliding again and lead us quickly into the abyss of violence and bloodshed"
Terje Roed-Larsen, UN envoy
But despite the strong words from both sides, the ceasefire between Israel and Hezbollah held into its second week.
Olmert, due to host senior UN envoys in Jerusalem, spoke to Romano Prodi, the Italian prime minister, late on Sunday and said he would be happy to see the Italians in charge.
Prodi also spoke to Fouad Siniora, the Lebanese prime minister, as diplomats strove to shore up the truce.
The Lebanese cabinet was due to meet on Monday to welcome the Italian initiative. A senior Lebanese political source said 2,500 Italian soldiers would take part in the UN contingent.
The UN force will work alongside a similar-sized Lebanese army contingent gradually deploying to the war-shattered towns and villages of southern Lebanon.
The ceasefire ended a fierce 34-day war which killed nearly 1,200 people in Lebanon and 157 Israelis.
Despite the apparent progress, the UN envoy to the Middle east, Terje Roed-Larsen, warned the ceasefire might still unravel.
"We are at the tilting edge still," he said. "This can easily start sliding again and lead us quickly into the abyss of violence and bloodshed."