The media arm of Al-Qaeda's Yemen branch said on the Twitter that the explosives were planted Thursday outside the house of President Abdrabuh Mansur Hadi, according to the SITE Intelligence Group.
They were intended to be detonated when Ambassador Matthew Tueller left following a visit to the house in the Yemeni capital Sanaa, it said.
There was no official confirmation of the failed plot.
Yemen is a key US ally in the fight against Al-Qaeda, allowing Washington to conduct a longstanding drone war against the group on its territory.