Washington (CNN) -- The United States has seen the first preliminary signs that Russian forces may be preparing to move away from Ukraine's eastern border, a U.S. defense official told CNN on Wednesday.
"There is some evidence of preparations for potential movement," the official said. "At a few locations, there is evidence of troops packing up, but nothing has moved yet."
The official declined to be identified because of the sensitivity of the information. The official also declined to specify the locations and emphasized that actual movement has not yet occurred.
This latest assessment was made days after Russia formally announced it had ordered its troops off the border. And it comes ahead of Ukraine's presidential election scheduled for Sunday.
The United States has estimated that 40,000 troops were on the border. Ever since the latest announcement, the United States has been watching for signs of movement to show up in satellite imagery from the area.
Russian President Vladimir Putin ordered tens of thousands of troops near the Ukraine border to return to their bases, his spokesman Dmitry Peskov said Monday. The withdrawal has started, he said, and could take some time to finish.
But despite Moscow's assertion, there were no signs of the troops' withdrawal, NATO Secretary General Anders Fogh Rasmussen said hours later.
The United States, which along with other Western countries has sanctioned Russia for its disputed takeover of Crimea, has threatened additional punishment for Russia if it fails to pull its troops back from the border.
Putin: 'Our troops are no longer on the border'
On Wednesday, Putin said that "our troops are no longer on the border," the Kremlin website said. The President made the remarks during a trip to Shanghai, China, it said.
"They really were quite close to the border and you certainly heard about that. A while back I gave the command to the Ministry of Defence to withdraw them to their training grounds. They are also located in the adjacent regions, in Rostov region, nearby. But now the Ministry of Defence received another instruction. To withdraw them even from these training grounds," he said.
Putin said the upcoming elections factored into his decision.
"I would like to stress again it is done not because we are embarrassed to keep our troops there -- we are a sovereign state and we keep our troops where we want to -- but to be able to set up extra favorable conditions around the coming presidential elections in Ukraine. To avoid any speculation about that, such a decision was made," he said, according to the website.
Detained journalist freed
A journalist detained Tuesday in Ukraine was freed Wednesday, according to his Twitter account.
The Ukrainian Foreign Ministry confirmed to CNN that Russia Today journalist Graham Phillips had been detained and turned in to the Security Service of Ukraine.
He sent a series of tweets Wednesday saying he had been freed and describing his detention.
"All my work in order, no charges, no deportation, no one laid a hand on me in anger, Ukrainian authorities treated me fairly. All ok," he tweeted. He thanked the British Embassy for its help in his case.
The exact circumstances of his detention were not immediately clear, but RT.com said he had been arrested at a checkpoint in Mariupol. In the tweets before his detention, Phillips described a secret interview at the city morgue.
CNN's Anna Maja Rappard, Olga Pavlova, Victoria Butenko and Carol Jordan contributed to this report.