Amos Hochstein, a top U.S. envoy to the Middle East, arrived in Beirut, the Lebanese capital, on Tuesday as efforts to broker a cease-fire between Israel and Hezbollah appeared to be intensifying.

A senior U.S. official said on Tuesday there was a "real opportunity" to end the conflict between Israel and Hezbollah and that gaps were narrowing, signalling progress in Washington's efforts to clinch a ceasefire agreement.

Some of the weapons, which include modern antitank missiles, have come from Russian stockpiles in neighboring Syria.