A tree gifted to President Donald Trump by French President Emmanuel Macron has disappeared from the White House lawn.
The pair planted the sapling, taken from the site of a World War One battle in north-east France, last week.
Mr Macron said the tree would be a reminder of "these ties that bind us".
But a Reuters photographer on Saturday took a shot of only a yellow patch of grass where the tree once stood. The French ambassador to the US later tweeted the sapling was in quarantine.
100 years ago, American soldiers fought in France, in Belleau to defend our freedom. This oak tree (my gift to @realDonaldTrump) will be a reminder at the White House of these ties that bind us. pic.twitter.com/AUdVncaKRN— Emmanuel Macron (@EmmanuelMacron) April 24, 2018
The tree, a European sessile oak, came from the site of the Battle of Belleau Wood, which took place in the summer of 1918.
Nearly 2,000 US soldiers died in the battle north-east of Paris.
Yet only four days after it was planted, the sapling has disappeared.
With no official reason given for the sapling mystery, speculation began online about the tree's fate.
French radio network Franceinfo quotes gardening site gerbaud.com, which says this type of oak is better planted in autumn, giving it time to grow deep roots "to face the drought of the following summer".
"The tree may be back in October," Franceinfo speculates.
Later, French Ambassador Gerard Araud said the sapling had been placed in quarantine.
It is in quarantine which is mandatory for any living organism imported to the US. It will be replanted afterwards. https://t.co/XyJRKTgPWW— Gérard Araud (@GerardAraud) April 29, 2018
Mr Araud also sought to placate concerns about the tree having been planted at all.
The roots, he explained, had been wrapped in plastic.
No. The roots were enclosed in a plastic protection. https://t.co/3HkZgl08m1— Gérard Araud (@GerardAraud) April 29, 2018
The US Customs and Border Protection website explains that foreign plants "intended for growing (propagative) require a foreign phytosanitary certificate in advance" before being brought into the country.
President Macron's gift quickly became an internet sensation, with a photo of the two men shovelling earth onto the sapling quickly turning into a meme.
The new Sopranos season is the best pic.twitter.com/IAgj3gLvm3— Mathieu von Rohr (@mathieuvonrohr) April 24, 2018
which pink floyd album is this pic.twitter.com/a0uQx6rsNp— Hunter Lurie (@hunterlurie) April 23, 2018