President Donald Trump said on Sunday his administration is talking to seven countries about helping to secure the Strait of Hormuz amid the U.S.-Israeli war on Iran, calling on them to help protect ships in the vital waterway that Tehran has mostly blocked to oil tanker traffic.

With the conflict creating turmoil across the Middle East and shaking up global energy markets in its third week, Trump insisted that nations relying heavily on oil from the Gulf have a responsibility to protect the strait.

"I'm demanding that these countries come in and protect their own territory, because it is their territory," Trump told reporters aboard Air Force One on the way from Florida to Washington.

Though he declined to identify the governments that his administration has contacted, Trump said this weekend that he expected many countries would send warships to allow shipping through the Strait of Hormuz, a conduit for 20% of the world's oil.

He said in a social media post he hoped China, France, Japan, South Korea, Britain and others would participate.

Trump also said Washington is in contact with Iran but expressed doubt that Tehran is prepared for serious negotiations to end the conflict.

U.S. officials responding to economic uncertainty over high oil prices predicted on Sunday that the war on Iran would end within weeks and that a drop in energy costs would follow, despite Iran's assertion that it remains "stable and strong" and ready to defend itself.

Trump had threatened more strikes on Iran's main oil export hub Kharg Island over the weekend and said he was not ready to reach a deal to end the war which has shut off the vital Strait of Hormuz.

The Trump administration plans to announce as early as this week that multiple countries have agreed to form a coalition to escort ships through the narrow waterway but they are still discussing whether those operations would begin before or after hostilities end, the Wall Street Journal reported, citing unnamed U.S. officials. The White House did not immediately respond to a request for comment.

Trump, who on Friday said the U.S. Navy would "soon" start escorting oil tankers, has said Iran wants to negotiate, but Iranian Foreign Minister Abbas Araqchi on Sunday disputed that claim.

“We have never asked for a ceasefire, and we have never asked even for negotiations," Araqchi told CBS' "Face the Nation" program. "We are ready to defend ourselves for as long as it takes.”

With crude oil prices hovering around $100 a barrel, Trump administration officials insisted that all signs point to a relatively quick end to the conflict.

"This conflict will certainly come to the end in the next few weeks — could be sooner than that ... and we'll see a rebound in supplies and a pushing down of prices after that," U.S. Energy Secretary Chris Wright told ABC's "This Week" program.