The U.S. journal Foreign Policy has reported that Belarus has lifted a long-standing limit on the number of U.S. diplomats allowed in the country.
There was no immediate confirmation of the move from Belarusian officials.
The reported improvement follows months of increased engagement with Belarus by U.S. President Donald Trump's administration. It would be a diplomatic breakthrough with Belarus at a time that its ties with Russia are fraying over an energy dispute.
"It's a big step. This is the beginning of a thaw," an unnamed U.S. official was quoted as saying in the January 10 issue of Foreign Policy.
In Minsk, a Foreign Ministry spokesman told RFE/RL's Belarusian Service that senior officials from Belarus and the U.S. have recently discussed ways to improve bilateral relations.
But the spokesman, Anatol Hlaz, declined to confirm the report, or reveal more details of the conversations.
"In accordance with diplomatic ethics, the contents of such conversations should not be disclosed," Hlaz said.
Citing two diplomatic sources briefed on the matter, Foreign Policy said that Belarusian Foreign Minister Uladzimer Makey had informed U.S. Assistant Secretary of State for European and Eurasian Affairs Wess Mitchell of the decision in a January 10 phone call.
The decision partially reverses a decline in diplomatic relations between Washington and Minsk that dates back to the first years after the collapse of the Soviet Union.
The State Department declined to comment, saying its press operations were on a "reduced status" because of the ongoing shutdown of the U.S. government.
The reported move comes amid a political clash between Belarusian President Alyaksandr Lukashenka and Russian President Vladimir Putin.
Belarus has long benefited from buying subsidized oil products from Russia and reexporting them, but Russia now plans to charge higher prices for crude to lessen the burden on its economy.
Lukashenka warned Russia earlier this week that it could lose its ally if Moscow fails to offer Minsk compensation for higher oil prices.
BelTA quoted Lukashenka as saying on January 10 that if the Kremlin chose a path that causes Moscow to lose Minsk as an ally, the development would be the result of "their choice."
The last U.S. ambassador posted to Minsk was expelled in 2008 after the United States imposed additional sanctions on Belarus, citing the country's deteriorating human rights situation and Lukashenka's authoritarian rule.
Thirty of the 35 diplomats serving in the country were also expelled.
Foreign Policy quoted diplomatic sources as saying that since 2008, Belarus had limited the number of U.S. officials serving at the embassy to five, and later 10.
The U.S. Embassy in a country the size of Belarus typically would have about 30 staff members, not including local hires, the report said.