A senior U.S. official has offered a positive assessment of the situation in Lebanon. But in an appearance before Congress Wednesday, the official acknowledged that disarming Hezbollah remains a key challenge.

David Welch (file photo)

The State Department's Assistant Secretary for Near Eastern Affairs, David Welch, appeared before the Senate Foreign Relations Committee to offer an assessment of the situation in Lebanon a month after a ceasefire ended the conflict there between Israel and Hezbollah.

"Disarmament of militias is a continuing challenge inside of Lebanon, particularly with respect to Hezbollah. This is a significant challenge internally and politically inside of Lebanon, but we believe it is necessary for a lasting peace, and necessary also for Lebanon's assertion of its sovereignty," he said.

Welch noted that a key task of a U.N. force in Lebanon will be to ensure that no arms are smuggled across the border to Hezbollah.

Syria and Iran are widely believed to have provided Hezbollah with arms and money in the past.

Welch warned of consequences if the arms embargo is violated now.

"Should it happen, I think we'll bring the matter up before the Council to present whatever evidence is available so that Syria or whoever is doing it would be held to account," he said.

In general, Welch offered a positive assessment of recent developments in Lebanon, particularly the establishment of the U.N. peacekeeping force to patrol border areas.

"As of September 6, there was troop commitments of nearly 9,000 and just in the last week or so, an additional government decision on participation. Over 3,000 fresh troops are on the ground, and more arriving every day," he said.

Germany's cabinet Wednesday voted to send warships to the region to lead a multi-naval force patrolling the coastline, and the German parliament is expected to approve the decision next week.