We reported in our 13.04 post that Poland and the Baltic states will close their borders with Belarus entirely if there is a "critical incident" involving Wagner mercenaries.
In an update, Lithuanian interior minister Agne Bilotaite has told reporters there are two main criteria that could lead to such a closure.
"First of all, an armed incident at the border of one of the countries," she said.
Poland and Latvia also have borders with Belarus.
Ms Bilotaite added: "The incident would need to pose a serious threat to national security."
She continued: "The other criterion is a mass breakthrough of migrants through the border of one of the states."
Ms Bilotaite said her ministry's proposal to close two of her country's four remaining border crossing points with Belarus would curb contraband and concentrate more officers at the remaining border crossings.
Poland has closed all but one crossing point with Belarus this year.
It follows the imprisonment of a journalist of Polish origin and expulsions of Polish diplomats.
