LONDON, April 28 (Reuters) - The United Arab Emirates, one of OPEC+'s largest producers, will leave the oil producers' alliance on May 1, it said on Tuesday.

The Organization of the Petroleum Exporting Countries and allies, including Russia, are known collectively as OPEC+. Last year, the group produced nearly 50% of the world's oil and oil liquids, according to International Energy Agency estimates. The UAE is the fourth largest producer in OPEC+.

Below are facts about OPEC+ and its role.

WHAT ARE OPEC AND OPEC+?

LONDON, April 28 (Reuters) - Britain said on Tuesday the Iranian ambassador to London had been summoned over what the government described as the Iranian embassy's "unacceptable and inflammatory" comments on social media.

Britain's minister for the Middle East, Hamish Falconer, made clear that the embassy "must cease any form of communications that could be interpreted as encouraging violence in the UK or internationally", the Foreign Office said in a statement.

Iranian officials in Tehran could not be immediately reached for comment on Britain's move.

By Leila Miller

BUENOS AIRES, April 28 (Reuters) - Argentine President Javier Milei, a libertarian who has long cited former British Prime Minister Margaret Thatcher as one of his political role models, has recently sharpened his public tone on the Falkland Islands, a contrast from the moderate approach he has previously adopted as he's sought closer ties with the West.

A pirate attack off Somalia is the work of a new group of "opportunistic criminals", security officials said on Tuesday, complicating a threat that costs the shipping industry billions of dollars.

Piracy was rampant off the coast of Somalia in the 2000s, peaking in 2011 with hundreds of attacks, but was significantly reduced by international naval deployments and new tactics by commercial shipping.

Yet the past week has seen oil tanker HONOUR 25 and cement carrier SWARD hijacked in the first major incidents in months.

ANKARA, April 28 (Reuters) - Turkey's pro-Kurdish DEM Party issued one of its strongest criticisms yet of the government's handling of a fragile peace process, highlighting on Tuesday a growing stand-offbetween Ankara and Kurdish militants over next steps to end a decades-long conflict.

DEM is parliament's third biggest party and helped facilitate steps toward peace between the Turkish state and the Kurdistan Workers' Party (PKK), whose conflict has killed more than 40,000 people since 1984.

By Samia Nakhoul, Parisa Hafezi and Asif Shahzad

DUBAI, April 28 (Reuters) - Two months into a war with the U.S. and Israel, Iran no longer has a single, undisputed clerical arbiter at the pinnacle of power — an abrupt break with the past that may be hardening Tehran’s stance as it weighs renewed talks with Washington.

By Daniel Flynn

KYIV, April 28 (Reuters) - President Volodymyr Zelenskiy has leveraged Ukraine's expertise in drone warfare into a series of successful diplomatic deals during visits to the Middle East and Europe, showcasing how Kyiv is using military prowess to boost its diplomatic clout.

This month alone, Ukraine has signed defence and drone deals in Germany, Norway and the Netherlands, following long-term security partnerships with Saudi Arabia, Qatar and the United Arab Emirates in late March.

The United Arab Emirates will withdraw from the OPEC and OPEC+ oil cartels to focus on "national interests", it announced on Tuesday, causing fresh shockwaves as energy prices soar over the Middle East war.

The UAE, one of the world's top oil producers, which has previously chafed at OPEC production quotas, will pull out on Friday, a statement carried by the official WAM news agency said.

The UAE has been an OPEC member through the emirate of Abu Dhabi since 1967, four years before the former British protectorate became a country.

WASHINGTON, April 28 (Reuters) - President Donald Trump said on Tuesday that Iran has said it was in a state of collapse and wants the United States to open the Strait of Hormuz while it sorts out its leadership.

It was not clear from Trump's social media post how Iran had communicated that message and no immediate comment from Iran was available.

April 28 (Reuters) - A superyacht owned by Russian billionaire Alexey Mordashov was able to transit the blockaded Strait of Hormuz after undergoing maintenance in Dubai because neither Iran nor the United States objected, a source close to Mordashov said on Tuesday.

It has been unclear how the multi-deck pleasure vessel, worth over $500 million, gained permission to sail on Saturday through the commercially important waterway at the heart of the U.S.-Iran conflict, where traffic has been severely restricted since February.