Iran said Wednesday that exchanges with the United States via Pakistan had continued following failed negotiations over the weekend.

"Since Sunday, when the Iranian delegation returned to Tehran, several messages have been exchanged through Pakistan," said foreign ministry spokesman Esmaeil Baqaei in a weekly press briefing.

Senior UAE and Iranian officials held a call to discuss de-escalation on Wednesday, UAE state media reported, the first high-level call since ties deteriorated over the U.S.-Iran war.

United Nations refugee chief Barham Salih on Wednesday called on the international community to provide urgent support to Lebanon, with a fifth of the country's population displaced by the Israel-Hezbollah war.

"I call upon the international community to provide urgent support and relief to Lebanon," he said after meeting Lebanese Prime Minister Nawaf Salam.

There are few precedents for the direct talks between Lebanese and Israeli officials that began in Washington on Tuesday.

- 1949, Fragile armistice -

Iran's military warned on Wednesday it would block trade through the Red Sea, along with the Gulf and Sea of Oman, if the U.S. naval blockade continues.

In a statement carried by Iranian state television, the head of Iran's military central command center said if the U.S. continues with its blockade and "creates insecurity for Iran's commercial vessels and oil tankers", it will constitute "a prelude" to violating the ceasefire.

Israel's military on Wednesday issued a fresh evacuation order for residents of south Lebanon despite talks held Tuesday in Washington.

"The airstrikes are ongoing as the Israel Defense Forces operate with significant force in the area. Therefore... we reiterate our urgent appeal for you to evacuate your homes immediately and head north of the Zahrani River," it said in a statement.

The Israeli military has said that three Hezbollah militants were brought to Israel for questioning after surrendering during close-quarters combat in southern Lebanon.

"Yesterday, IDF soldiers engaged in close-range combat with a Hezbollah terrorist cell in Bint Jbeil," the military said.

Israel's army said Hezbollah militants fired around 30 rockets into northern Israel early on Wednesday, just hours after Washington hosted the first direct talks between Israel and Lebanon in decades.

The military detected "approximately 30 launches" towards Israel since the early hours, a spokesman told AFP.

Two Israeli strikes on Wednesday hit vehicles south of Beirut, state media reported, while Hezbollah launched rockets at Israel, hours after Lebanon and Israel agreed to hold direct negotiations.

Israel is continuing its strikes on southern Lebanon, but has not targeted the Lebanese capital since a series of attacks across the country on April 8 that killed more than 350 people.

U.S. President Donald Trump told the New York Post on Tuesday that a second round of Iran talks could happen in Pakistan "over the next two days," after a first round ended at the weekend without a deal.