Supreme leader Ayatollah Ali Khamenei on Saturday acknowledged the economic demands of protesters in Iran, where demonstrations have spread to more than two dozen cities, even as he warned there would be no quarter for "rioters".

The protests began on Sunday as an expression of discontent over high prices and economic stagnation, but have since expanded to include political demands.

Iranian media have reported localised violence and vandalism in the west of the country in recent days.

DUBAI, Jan 3 (Reuters) - The United Arab Emirates said on Saturday it was deeply concerned by ongoing escalation in Yemen after Saudi-backed government forces swept into areas seized last month by UAE-backed southern separatists seeking independence.

The rapidly moving crisis in Yemen has opened a major feud between the two Gulf powers and fractured the coalition of forces, headed by the internationally recognised government, who are fighting the Iran-backed Houthi movement.

WASHINGTON, Jan 2 (Reuters) - UN Secretary-General Antonio Guterres is deeply concerned by Israel's announcement of a suspension of the operations of several international non-governmental organizations in occupied Palestinian territory and called for the measure to be reversed, according to a statement on Friday.

UN Secretary General Antonio Guterres called on Friday for Israel to end a ban on humanitarian agencies that provided aid in Gaza, saying he was "deeply concerned" at the development.

Guterres "calls for this measure to be reversed, stressing that international non-governmental organizations are indispensable to life-saving humanitarian work and that the suspension risks undermining the fragile progress made during the ceasefire," his spokesperson Stephane Dujarric said in a statement.

Iran has been rocked this week by protests that started in Tehran and have spread to other cities, with at least six people killed in clashes with security forces.

Official media has largely played down the protests but videos have flooded social media, many of which are difficult to authenticate, or have even been manipulated.

Here is a recap of what we know and what analysts think it all means.

- What's going on? -

The protests began on Sunday in Tehran, where some shopkeepers went on strike over high prices and economic stagnation.

Jan 2 (Reuters) - Yemen's southern separatist movement said on Friday it aims to hold a referendum on independence from the north in two years following its seizure of swathes of the country last month in a move that triggered a major feud between Gulf powers.

The Southern Transitional Council (STC) is backed by the United Arab Emirates and has for years been part of Yemen's internationally recognised government which is supported by Saudi Arabia and has led the fight against the Houthi movement.

ROME, Jan 2 (Reuters) - Emanuele Galeppini, a 16-year-old Italian international golfer who lived in Dubai, was named on Friday as the first of several possible victims from Italy to be identified after a New Year's Eve bar fire in the Swiss ski resort of Crans-Montana.

"The Italian Golf Federation mourns the passing of Emanuele Galeppini, a young athlete who carried with him passion and genuine values," the federation said in a statement.

ANKARA, Jan 2 (Reuters) - Turkish President Tayyip Erdogan said he would have a phone call with U.S. President Donald Trump on Monday to discuss peace efforts between Ukraine and Russia as well as issues surrounding Gaza.

Speaking to reporters in Istanbul on Friday, Erdogan also said Turkey's Foreign Minister Hakan Fidan will attend a meeting of the "Coalition of the Willing", a group of nations backing Ukraine, in Paris in coming days.

(Reporting by Huseyin Hayatsever; Editing by Jonathan Spicer )

By Yousef Saba

DUBAI, Jan 2 (Reuters) - Yemen's more than decade-long civil war has flared up after a United Arab Emirates-backed separatist movement swept through territory in the south, splintering the Saudi-led coalition that was created to fight the Iran-aligned Houthi group.

Below are details of the key factions in the conflict in Yemen, which has caused one of the world's worst humanitarian crises:

THE HOUTHIS

President Donald Trump said on Friday that the United States was "locked and loaded" to respond if Iran killed protesters, prompting Tehran to warn that intervention would destabilise the region.

Protesters and security forces clashed in several Iranian cities on Thursday, with six people reported killed, the first deaths since the unrest escalated.

Shopkeepers in the capital Tehran went on strike on Sunday over high prices and economic stagnation, actions that have since spread into a protest movement that has swept into other parts of the country.