US President Donald Trump has options to intervene in protest-hit Iran that range from low to high risk, but choosing his course depends on him deciding his ultimate goal.

It has been 10 days since Trump said the United States was "locked and loaded" and ready to "come to the rescue" if Iran's clerical state kills demonstrators who have taken to the streets in major numbers.

Since then, Trump has kept threatening a military option, even as hundreds of people have died, according to rights groups.

WASHINGTON, Jan 12 (Reuters) - U.S. President Donald Trump said on Monday that any country that does business with Iran will be subjected to a tariff rate of 25% on any business conducted with the United States.

"Effective immediately, any Country doing business with the Islamic Republic of Iran will pay a Tariff of 25% on any and all business being done with the United States of America," Trump said in a post on Truth Social.

"This Order is final and conclusive," he said.

(Reporting by Kanishka Singh and Bhargav Acharya)

Jan 12 (Reuters) - Ukrainian President Volodymyr Zelenskiy said on Monday that the world had to help Iranians build on protests to engineer change to free them from rule that brought evil to their own and other countries, including Ukraine.

Zelenskiy, speaking in his nightly video address, described the nationwide protests gripping Iran as an "uprising".

He said the unrest showed that Russia had to rethink its close links with Iran, which have included its wide use of Iranian-made "Shahed" drones in the nearly four-year-old war against Kyiv.

By Supantha Mukherjee, Cassell Bryan-Low and Parisa Hafezi

Jan 12 (Reuters) - Some Iranians are still using Elon Musk’s Starlink satellite internet service despite a nationwide communications blackout, three people inside the country said, the latest example of Starlink being used to counter internet shutdowns in geopolitical flashpoints.

Iranian authorities have in recent days launched a deadly crackdown on nationwide protests, including the near-complete shutdown of internet service, which is provided through fiber-optic cables and cellphone towers.

Israel will take part in the first semi-final of the Eurovision Song Contest on May 12 in Vienna, according to the draw on Monday, as five countries are staying away this year over Israel's participation.

The world's biggest live televised music event heads into its 70th anniversary edition mired in its biggest-ever political boycott, with just 35 countries set to part -- the fewest since entry was expanded in 2004.

US President Donald Trump is considering air strikes on Iran to stop a crackdown on protesters, the White House said Monday, adding that people were being "killed on the streets."

But a channel for diplomacy remains open, with Iran taking a "far different tone" in private discussions with Trump's special envoy Steve Witkoff, said Press Secretary Karoline Leavitt.

By Daphne Psaledakis

WASHINGTON, Jan 12 (Reuters) - The U.S. State Department said on Monday it has revoked more than 100,000 visas since President Donald Trump took office last year, setting what it said was a new record as his administration pursues its hardline immigration policy.

The UK government has paid "substantial" compensation to a Guantanamo detainee who was tortured by the CIA and has been held there without charge for two decades, his lawyer said Monday.

Abu Zubaydah, 54, was the first of a number of prisoners to be subjected to CIA "enhanced interrogation" techniques following the September 11, 2001, attacks on the United States.

The Saudi-born Palestinian -- whose full name is Zayn al-Abidin Muhammad Husayn -- was captured in Pakistan in 2002 and has been held without trial at the US Guantanamo Bay military camp in Cuba since 2006.

MOSCOW, Jan 12 (Reuters) - Sergei Shoigu, Secretary of Russia's Security Council, held a telephone conversation with the Secretary of Iran's Supreme National Security Council, Interfax reported on Monday.

During the call, Shoigu strongly condemned what he described as attempts by foreign powers to interfere in Iran’s internal affairs.

Both sides agreed to maintain contacts and coordinate their positions to strengthen security.

(Reporting by Maxim Rodionov; Editing by Nia Williams)

By Parisa Hafezi

DUBAI, Jan 12 (Reuters) - Iran's bazaar merchants, the trader class who were the financial backbone of the 1979 Islamic Revolution, have turned against the clerics they helped bring to power, fuelling unrest over an economy that has morphed into full-blown anti-government protests.