The spokesperson for UK Prime Minister Rishi Sunak said he will visit the United States on Monday to meet Biden and Australian Prime Minister Anthony Albanese for talks on the AUKUS defence agreement.

Sources familiar with the planning said that trilateral summit would take place in San Diego on Monday to unveil new details of the 2021 AUKUS pact conceived as part of efforts to counter China in the Pacific region.

Albanese said before leaving on a visit to India on Wednesday he would visit the United States to meet Biden but would not be drawn on plans for a summit with Biden and Sunak.

“I look forward to the continuing engagement that I have with the US administration,” Albanese told reporters before departure for India, without giving a date for his US trip.

Australia’s ambassador to the United States Arthur Sinodinos said last week that details of the submarine deal would be announced in mid-March.

San Diego is home to the US Pacific Fleet and a source familiar with the planning told Reuters the trilateral summit could involve a visit to a submarine.

While the US and the UK have agreed to provide Australia with the technology to deploy nuclear-powered submarines, the three allies have yet to say exactly how the capability will be transferred to Australia, which does not have a nuclear-propulsion industry.

AUKUS will be Australia’s biggest-ever defence project and offers the prospect of jobs in all three countries but it remains unclear whether it will involve a US or a UK-designed submarine, or a combination of both, or when the vessels will become operational.

Australian defence industry speculation has centred on Australia opting for a UK design while Sinodinos said there would be a “genuine trilateral solution”.

Despite an 18-month consultation period since AUKUS was first announced, questions remain over strict US curbs on technology sharing needed for the project.

These are a particular concern for its so-called pillar two dealing with advanced technology programs such as artificial intelligence and hypersonic weapons.

UK and Australian officials said last week work was still needed to break down bureaucratic barriers to technology sharing in pillar two and the top Pentagon official for Asia, Ely Ratner, referred to “antiquated systems” governing US technology.

Ratner said these needed to be revised “and we’re in the process of doing so”.

A State Department spokesperson said the US was “actively working to re-examine and streamline our processes to optimise our defence trade in the AUKUS context,” and added: “We do not anticipate any challenges in implementing AUKUS due to US export-control regulations.”

However, despite political will for reform in US President Joe Biden’s administration, experts question how easy it will b for AUKUS to avoid the attentions of mid-level State Department bureaucrats duty bound to protect US defence technology.

Ashley Townshend, an Australian defence expert at the Carnegie Endowment for International Peace think tank, said a new information-sharing agreement would be needed for the submarine program’s implementation stage.

“I have no doubt that this will happen,” he said.

“But unless the agreement covers every single technology and defence service that the submarine program will involve, over the course of its lifetime, it won’t be immune to bureaucratic and regulatory constraints.”

Some experts believe the AUKUS announcement could include plans to station US and UK nuclear submarines in Australia to train Australian crews and fill a capability gap until the new Australia submarines are in service, which is not expected until about 2040.