On Saturday, Welch visited Parliament Speaker Nabih Berri, a prominent Shi'ite Muslim who has been negotiating on behalf of Hizbullah in the conflict.
It was not clear whether Welch would then hold another meeting with Saniora.
Lebanese army troops deployed heavily in central Beirut and dozens of soldiers blocked the way toward the Grand Serail, Lebanon's seat of government, in anticipation of anti-US protests timed to coincide with Welch's visit.
By midday, about 120 people had converged on the area, shouting anti-American slogans. "Welch, out!" and "America is the great Satan!" they chanted. The protesters were mostly from the Lebanese Communist Party and other pro-Hizbullah groups.
The State Department said Friday that the United States and France were near completion of a UN resolution designed to halt the 25-day fighting in Lebanon and to set out principles for a lasting cease-fire.