UN Secretary General Kofi Annan said that he was "deeply concerned about a violation by the Israeli side" of the ceasefire in southern Lebanon.
A statement issued through Annan's spokesman from UN headquarters in New York was made in response to a raid by Israeli special forces on Saturday in eastern Lebanon. It also alleged "several air violations" by Israeli military aircraft.
Resolution 1701, which took effect on August 14, demanded a halt to rocket and ground attacks by the Lebanese Hezbollah militia and an end to offensive military action by Israel in southern Lebanon.
"All such violations of Security Council resolution 1701 endanger the fragile calm that was reached after much negotiation and undermine the authority of the government of Lebanon," the statement said.
Annan called on "all parties to respect the arms embargo, exercise maximum restraint, avoid provocative actions and display responsibility in implementing resolution 1701."
Earlier on Saturday, Annan and French President Jacques Chirac agreed in telephonic talks that the first units of a strengthened UN peacekeeping force in southern Lebanon should be sent as soon as possible.
The French presidential office said that Chirac and Annan agreed that the troops need to be sent without delay. France has agreed to contribute an additional 200 troops to guard the ceasefire to the 200 French soldiers already participating in a smaller, longstanding UN force in southern Lebanon. The total French force is far short of the major, commanding role that many had foreseen for Lebanon's former colonial power.
The first contingents of the additional French troops began arriving on Saturday in Lebanon. The UN ceasefire resolution authorised the expansion of the existing force of 2,000 UN observers to 15,000 peacekeeping troops.
The UN has struggled so far to gain troop commitments from potential participating governments, as the rules of engagement remain under negotiation.