Belarusian state airline Belavia has stopped allowing citizens from Afghanistan, Iraq, Lebanon, Libya, Syria and Yemen to board flights from Uzbekistan's Tashkent to Minsk, the Belta news agency cited the carrier as saying on Thursday.
The European Union has accused Belarus of flying in migrants, mainly from the Middle East, and pushing them to illegally cross the border with Poland in a hybrid attack at the bloc. Belarus denies fuellng the crisis.
On Thursday Lebanon said that only foreigners with Belarusian residency permits would be allowed to fly from Beirut to the ex-Soviet country.
"Many Arab and foreign travelers have recently arrived in Belarus from Beirut via flights of various airlines," including Belarus's state-run Belavia airline, the transport ministry's directorate general of civil aviation said.
"It was later discovered that the purpose of their travel was to move to the border with Poland" and enter European Union territories, "in cooperation with smuggling networks", it said in a statement.
All airlines operating from Beirut must limit passengers departing on direct or indirect flights to Belarus to Belarusian citizens, Lebanese citizens holding visas or residency permits for Belarus, and "Arabs and foreigners having residency permits in Belarus".
It said the measures were effective immediately until further notice.