By Elizabeth Piper and Sarah Young

LONDON, March 15 (Reuters) - Prime Minister Keir Starmer said on Monday Britain would not be drawn into a wider war in Iran but would work with allies on a "viable collective plan" to reopen the key Strait of Hormuz, though he acknowledged that would not be a simple task.

U.S. President Donald Trump has heavily criticised Starmer for not initially supporting the U.S.-Israeli strikes on Tehran, and said at the weekend that Britain, China, France, Japan and South Korea should send warships to the region to reopen the waterway.

By Alexander Cornwell and Maya Gebeily

TEL AVIV/BEIRUT, March 16 (Reuters) - Israel pushed into new parts of southern Lebanon on Monday, deploying troops to target Hezbollah positions as it intensified its campaign against the Iran-backed militant group.

In a briefing, Israeli military spokesperson Lieutenant Colonel Nadav Shoshani told reporters that soldiers were in "new locations that our troops were not operating yesterday".

Here are the latest developments Monday in the Middle East war:

- Oil prices jump -

The price of oil jumped more than five percent Tuesday as several countries pushed back against US President Donald Trump's demand that they help secure the key Strait of Hormuz, while Iran targeted crude-producing neighbours.

At around 0615 GMT, US benchmark West Texas Intermediate was up 5.16 percent at $98.32 a barrel while Brent Crude also rose above five percent before easing back.

LONDON, March 16 (Reuters) - Britain is working with allies on a collective plan to reopen the Strait of Hormuz and restore freedom of navigation in the Middle East but it will not be easy, British Prime Minister Keir Starmer said on Monday.

"Ultimately, we have to reopen the Strait of Hormuz to ensure stability in the (oil) market. That is not a simple task," Starmer told reporters.

NATO allies and other Western nations pushed back Monday on US President Donald Trump's demand that military alliance members help reopen the Strait of Hormuz, the critical conduit for crude oil Iran has effectively closed.

UK Prime Minister Keir Starmer said London was working with allies to craft a "viable" plan to reopen the strategic waterway but ruled out a NATO mission, while Berlin insisted it "has been clear at all times that this war is not a matter for NATO".

By Jarrett Renshaw and Steve Holland

PALM BEACH, Florida, March 16 (Reuters) - Neutralizing Iran could make crude oil much cheaper because the threat posed by Tehran imposed a "terror premium" that inflated global oil prices for decades, a top White House adviser said in a report to be released on Monday.

BRUSSELS, March 16 (Reuters) - French Foreign Minister Jean-Noel Barrot said on Monday that the European Union would impose sanctions on nine people accused of war crimes related to the Bucha massacre in Ukraine.

Barrot made the comments as he arrived at a meeting of EU foreign ministers in Brussels.

(Reporting by Dominique Vidalon; Editing by Sudip Kar-Gupta)

China and the US held what both sides described Monday as constructive talks aimed at addressing volatile trade ties that have been upended by President Donald Trump's tariffs and the Middle East war.

The talks in the French capital "were constructive and they show the stability of the relationship", US Treasury Secretary Scott Bessent told journalists.

Chinese state media described the Sunday talks between Bessent and Chinese Vice Premier He Lifeng as "candid, in-depth and constructive".

By Phuong Nguyen and Francesco Guarascio

HANOI, March 16 (Reuters) - Vietnamese authorities have warned the country's aviation industry to prepare for potential flight reductions from April after China and Thailand halted exports of jet fuel due to the Iran war, increasing the likelihood of shortages.

Vietnam imports more than two-thirds of its jet fuel needs, with 60% coming from China and Thailand, according to documents from the aviation regulator and importers seen by Reuters.

BEIJING, March 16 (Reuters) - China said on Monday it is in communication with the U.S. about President Donald Trump's visit, after Trump threatened to delay the trip over the Strait of Hormuz, and suggested sanctions previously imposed on Marco Rubio are no longer in effect.

Trump said countries that benefit from shipping through the Strait of Hormuz should help ​secure it, in comments published by the Financial Times on Sunday.