Ecuador's ambassador to the UK, Ana Alban, has told ITV News the microphone allegedly found inside her embassy is going to be sent away to be tested.
She said: "We found something, but we don't know what it is, and we are sending it to someone...I don't know how long it has been there."
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Ms Leadsom has received the backing of Ian Duncan Smith, the former work and pensions secretary.
The former shadow work and pensions secretary is considered a more viable candidate than Angela Eagle, a Labour source has told ITV News.
Between eight and 10 people have been rescued following the raid, according to Bangladeshi police.