By Yasmine Ghania and David LawderCAIRO/WASHINGTON, Aug 25 (Reuters) - Iran pledged to fight back against expanded U.S. sanctions aimed at isolating its economy, expressing confidence that major trading partners would resist the pressure campaign and saying that Washington was keen to revive talks.Almost six months into a conflict the U.S. has struggled to resolve, Treasury Secretary Scott Bessent unveiled the measures on Monday but stopped short of the most punishing sanctions.While he said countries that continued trading with Iran risked being forced out of the dollar-based financial system, he declined to give a timeline or identify which may be targeted, saying he would give them time to comply with the new directive.Abbas Golroo, head of the foreign relations committee in the Iranian parliament, said Pakistan's army chief Asim Munirhad delivered a message from the U.S. to Iran on Monday."It seems the main goal was to revive the stopped political process," he told ISNA news agency. There was no immediate comment from the White House or the State Department.The Treasury Departmentdid announcenew sanctions on 60 individuals, entities and vessels, but the list did not feature any of the Chinese financial institutions suspected of facilitating Iran's oil trade."We want to make clear here today that no one is above the reach of U.S. sanctions," Bessent said in response to a question about Chinese banks.China has been the biggest buyer of Iranian oil for several years, although the U.S. blockade of Iran's ports has cut Iranian oil flowsto China since Washington renewed it in mid-July.Experts say the U.S. is wary of Chinese retaliation for any sanctions on its banks ahead of expected talks next month between President Donald Trump and Chinese President Xi Jinping, with any curbs on China's exports of critical minerals especially sensitive.China said on Tuesday that its cooperation with Iran is conducted within the framework of international law and should not be interfered with or disrupted.Oil prices fell for a second day as traders brushed off the impact of the sanctions, although market participants remained wary of Iran's continued ability to disrupt shipping.OIL TANKER STRUCK NEAR STRAIT OF HORMUZAn oil tanker was struck on Tuesday by an unidentified projectile and disabled about 9 nautical miles (17 km) northeast of Oman's Ash Shishah, which lies at the entrance to the Strait of Hormuz, the United Kingdom Maritime Trade Operations said.After the latest sanctions were unveiled, Iranian Economy Minister Ali Madanizadeh said that Iran was prepared to respond."Our defense is no longer so defensive; the enemies should wait for an attack," he told state television. Neither China nor Russia had "accepted" the U.S. measures, he added, predicting that other countries would resist them.There have been no major U.S. or Iranian strikes for weeks, but Brigadier General Hossein Mohebbi, a spokesperson for Iran's Islamic Revolutionary Guard Corps, vowedheavy blowsto U.S. vital interests and energy chokepointsif Iran's infrastructure is threatened, Press TV reported.Iran and the United States signed an interim deal in June aimed at ending the war that began with U.S. and Israeli attacks on Iran in February, but it quickly faltered and Iran resumed ship attacks that have strangled energy exports from the Gulf.IRANIAN OFFICIAL PROMISES RESULTS OF MEDIATING VISIT SOONMediator Pakistan made "significant progress" in the latest talks with Tehran that focused on preventing further escalation and reopening the Strait of Hormuz, the Pakistani military said."We had a very constructive exchange," Pakistani Interior Minister Mohsin Naqvi, who accompanied Munirto Tehran, said on X.An official at the Iranian president's office, Mehdi Tabatabaei, posted that Munir's visit to Iran "yielded highly valuable diplomatic achievements, the results of which will soon be revealed".He did not elaborate, but the New York Times cited a State Department document saying that U.S. diplomats evacuated during the war could start returning to the Middle East as early as this week. Reuters could not immediately verify the report and it was unclear if it was linked to the mediation attempt.U.S. public approval of the war fell to its lowest level since the conflict's early days, with Trump's popularity at a record low ahead of congressional elections in November, a Reuters/Ipsos poll that closed on Monday showed.Oil transits through the Strait of Hormuz were at 5 million barrels per day on Monday, provisional tracking from shiptracker Vortexa showed, down from more than 20 million per day before the war or about one of every five barrels consumed worldwide.Thousands of people have died in the conflict, most of them in Iran and Lebanon, while much of Iran's conventional military capacity has been degraded, its economy is struggling andthen-Supreme Leader Ayatollah Ali Khameneiwas killed.But Iran is still able to attack Gulf neighbors and threaten oil tankers. The exact state of its nuclear program, which the U.S. and Israel aim to wipe out, remains unknown.(Additional reporting by Rick Noack in Islamabad, Yasmine Menna Alaa El Din and Nafisa Eltahir in Cairo; Writing by Daniel Trotta, Lincoln Feast, Philippa Fletcher; Editing by Clarence Fernandez and Sharon Singleton)