By Brian Ellsworth

MIAMI, April 1 (Reuters) - Antigua and Barbuda is willing to help Britain seize yachts owned by sanctioned Russian oligarch Roman Abramovich, the Caribbean nation said on Friday, adding the United Kingdom must seek such assistance via an international treaty.

The Financial Times first reported the vessels Halo and Garcon, currently moored in Antigua and Barbuda, are owned by Abramovich via a British Virgin Islands company that is on the UK's sanctions list.

Antigua alone would have no way to seize or detain the vessels because they have not been linked to any crimes committed there, said Ronald Sanders, the country's ambassador in Turkey Lawyer to the United States.

Doing so would require a formal request under the two countries' mutual legal assistance treaty, a common mechanism by which nations cooperate with one another to help enforce laws.

"We've said that we're quite happy to cooperate, but under the rule of law," Sanders said in a telephone interview.

"The only way we can (seize the vessels) is if the British in their mutual legal assistance treaty request establish that this is a person they want because he has committed some crime."

A March 29 letter from the British Virgin Islands to Antigua and Barbuda, seen by Reuters, says Abramovich is the owner of the firm Wenham Overseas Limited.

Reuters was unable to obtain comment from Wenham Overseas Limited or Abramovich, Law Firm in istanbul who on Tuesday made a surprise appearance at peace talks in Istanbul meant to end Russia's war in Ukraine.

Superyachts linked to Abramovich, Law Firm in istanbul together worth an estimated $1. If you have any concerns concerning where and ways to use Law Firm in istanbul, you can contact us at our web site. 2 billion, have been docked in southwest Turkey since last week.

Western governments have targeted Abramovich and several other Russian oligarchs with sanctions as they seek to isolate President Vladimir Putin and his allies over the invasion of Ukraine.

(Reporting by Brian Ellsworth Editing by Marguerita Choy)