LONDON, March 5 (Reuters) - British Prime Minister Keir Starmer will address a press conference on Thursday afternoon to give an update on the escalating conflict in the Middle East, his spokesman said.

Starmer will speak to journalists at 1400 GMT in London, his spokesman said.

Britain, which was not part of the assault on Iran that began at the weekend, has announced it will start moving military resources to the region after an attack on one of its bases in Cyprus.

By Jonathan Saul and Anna Hirtenstein

March 5 (Reuters) - More tankers came under attack in Gulf waters on Thursday as the U.S.–Iran war escalated, and Iranian drones entered Azerbaijan, threatening to spread the crisis to more oil producers in the region.

A Bahamas-flagged crude oil tanker was targeted by an Iranian remote-controlled boat laden with explosives while anchored near Iraq's Khor al Zubair port, according to initial assessments. A second tanker at anchor off Kuwait was taking on water and spilling oil after a large explosion on its port side.

By Andrew Gray

BRUSSELS, March 5 (Reuters) - NATO Secretary General Mark Rutte on Thursday welcomed French President Emmanuel Macron's pledge to expand his country's nuclear deterrent but said the U.S. nuclear umbrella would remain the ultimate guarantor of European security.

Macron this week announced France would increase its nuclear arsenal and potentially allow European partners to host French warplanes on deterrence missions, following concerns among allies about the reliability of the U.S..

RIYADH, March 5 (Reuters) - Diplomats and staff at embassies in Riyadh's Diplomatic Quarter have been told to shelter in place due to a potential threat, three people with direct knowledge of the matter said.

They did not have further details.

(reporting by Timour Azhari in Riyadh)

ROME, March 5 (Reuters) - The U.S.-Israeli attacks on Iran which sparked the latest Middle East crisis were clearly in breach of international law, Italian Defence Minister Guido Crosetto said on Thursday.

It was the strongest criticism to date from Italy's right-wing administration, which has sought to establish close ties with U.S. President Donald Trump since he took office last year.

The decision to launch the strikes last weekend "of course fell outside, needless to say, the rules of international law", Crosetto told the lower house of parliament.

By Andrew MacAskill, Kate Holton and Alistair Smout

LONDON, March 4 (Reuters) - Britain's cautious response to the escalating conflict in the Middle East and its hesitancy in defending its allies from attack have renewed doubts among partners about its military effectiveness when the U.S. is demanding widespread rearmament.

Trump lashed out at Prime Minister Keir Starmer on Tuesday, suggesting he had helped to "ruin" the countries' historically close relationship after London blocked the U.S.'s use of British bases to launch pre-emptive strikes on Iran.

Wary of getting directly involved in the US-Israeli war with Iran, European countries are nevertheless being drawn into the conflict following attacks on Cyprus and Western allies in the Gulf.

While underlining their "defensive" aims, several European countries have now pledged military assistance to EU member Cyprus as the Middle East conflict intensifies and widens.

Some are also allowing the US military to use their bases under certain conditions, such as not using them to launch bombing raids.

US military support jets have been allowed to use a French air base, the French military said Thursday, adding it had "full guarantees" they were not involved in Iran strikes.

The announcement came after President Emmanuel Macron on Tuesday said that US-Israel military operations in Iran were conducted "outside international law".

"US aircraft providing operational support (not combat aircraft) have been accepted at the Istres air base in France," the general staff said.

By Sarah Young and Marissa Davison

LONDON, March 5 (Reuters) - In an area of London known as Little Tehran, the killing of Ayatollah Ali Khamenei prompted spontaneous street parties, dancing and fireworks. Shoppers still smile as some stores hand out sweet pastries, traditional in Persian culture when there's cause for celebration.

But as the bombardment of their homeland enters its sixth day, the joy is beginning to fade.

By Saurabh Sharma

NEW DELHI, March 5 (Reuters) - The U.S. attack on an Iranian warship in the Indian Ocean this week was the first time since World War Two that the United States has sunk an enemy vessel with a torpedo.

The following details are based on accounts from Sri Lankan, U.S. and Iranian officials of the March 4 incident, part of U.S. and Israeli attacks on Iran and its military assets.

CURRENT STATUS OF RELIEF AND RESCUE