After talks in Washington on Tuesday that US Secretary of State Marco Rubio described as a "historic opportunity" for peace, Israel and Lebanon agreed to hold direct talks.
Iran talks could resume "over the next two days," according to US President Donald Trump, after the failure of last weekend's first round in Pakistan.
Six merchant ships turned around after "direction from US forces," according to the US, and no ships were able to pass through the blockade in the first 24 hours.
According to the Lebanese Ministry of Public Health, there were at least 35 deaths and 159 injuries in Lebanon on Tuesday.
The southern Lebanon district of Bint Jbeil has been hit by an Israeli airstrike.
"The short-term authorization permitting the sale of Iranian oil already stranded at sea is set to expire in a few days and will not be renewed," according to the US Treasury Department.
Republican South Carolina Senator Lindsey Graham has all but given up efforts to negotiate a compromise to end the U.S. government shutdown that would fund a U.S. Mexico border wall