By Michael Holden and Sarah Young

LONDON, April 23 (Reuters) - Britain's King Charles heads to the United States next week for the most high-profile trip of his reign so far, on a mission to shore up the future of the two allies' "special relationship" which the Iran war has plunged to its lowest point in 70 years.

The state visit marks the 250th anniversary of the U.S. declaration of independence from British rule, when the then 13 American colonies decided to split from King George III, Charles's five-times-great-grandfather.

A US naval blockade of Iranian ports is likely to squeeze Iran's oil output in the coming weeks but claims it will throw the Islamic republic into economic free fall remain premature, analysts say.

After weeks of bombing and counter-strikes, focus has shifted to the standoff in the Strait of Hormuz, which ordinarily carries around a fifth of the world's oil and liquefied natural gas.

The latest developments in the Middle East war:

- Iran gets first Hormuz toll -

A senior Iranian parliament official said on Thursday that Tehran has received the first revenue from tolls it imposed on the strategic Strait of Hormuz in its war with the United States and Israel.

"The first revenue received from the Strait of Hormuz tolls was deposited into the Central Bank account," said deputy speaker of parliament Hamidreza Hajibabaei, according to Tasnim news agency.

- Clearing Hormuz may take 6 months -

BEIRUT/JERUSALEM, April 22 (Reuters) - The U.S. will host a second meeting between Lebanese and Israeli envoys on Thursday, with Beirut seeking the extension of a ceasefire between Israel and Hezbollah, a day after Israeli strikes killed at least five people including a journalist.

The U.S.-mediated ceasefire, which is set to expire on Sunday, has yielded a significant reduction in violence, but attacks have continued in southern Lebanon, where Israeli troops have seized a self-declared buffer zone.

Iran-backed Hezbollah says it has "the right to resist" occupying forces.

BANGKOK, April 23 (Reuters) - The closure of the Strait of Hormuz has forced policymakers in Asia to face questions over the security of other maritime chokepoints, including the Strait of Malacca, which is the world's busiest waterway for international trade.

WHAT IS THE MALACCA STRAIT?

The 900-km (550-mile) long Malacca Strait, bounded by Indonesia, Thailand, Malaysia and Singapore, provides the shortest sea route from East Asia to the Middle East and Europe.

The Pentagon blasted as cherry picking and false on Thursday a news report saying that the department assessed it could take six months to completely clear the Strait of Hormuz of Iranian-laid mines.

The Washington Post reported on Wednesday that the Pentagon shared the six-month estimate during a classified briefing for the members of the House Armed Services Committee, citing three unidentified officials familiar with the discussion.

Iran's foreign minister arrived in Russia on Monday as peace efforts between Tehran and Washington hung in the balance, following a flurry of regional diplomacy and the collapse of planned talks in Pakistan.

Abbas Araghchi arrived in Saint Petersburg, the Iranian Foreign Ministry said on Telegram, where he is expected to meet with Russian President Vladimir Putin.

It comes after Araghchi visited Oman between trips to Pakistani capital Islamabad, as mediators push to keep peace talks between Tehran and Washington alive.

WASHINGTON/DUBAI/ISLAMABAD, April 23 (Reuters) - Iran seized two ships in the Strait of Hormuz as it tightened its grip on the strategic waterway after U.S. President Donald Trump announced he was indefinitely calling off attacks, with no sign of peace talks restarting.

Global stocks mostly fell Thursday, retreating after recent gains as investors tempered their enthusiasm for a quick end to the Middle East war.

The benchmark international oil contract, Brent North Sea crude, rose further above $100 a barrel, rekindling fears of pervasive inflation that could dent economic growth around the globe.

Wall Street's main indexes finished lower after a volatile session, joining most markets in Europe and Asia in retreating.

April 23 (Reuters) - Ukraine could face increased risks in securing U.S. anti-missile defences if the war in Iran goes on for an extended period of time, Ukrainian President Volodymyr Zelenskiy said on Wednesday.

Zelenskiy, interviewed by CNN, said Ukraine received limited numbers of such weaponry because U.S. production was limited, but so far it had experienced no disruption in supplies or in provision of intelligence.

Zelenskiy said Ukraine was able to secure U.S. weaponry through the PURL programme under which NATO countries can finance the purchase of weapons for Kyiv.