Belarus' leader Alexander Lukashenko ordered the closure of the border with Ukraine on Friday, seeking to block what he called an inflow of weapons to coup-plotters detected by his security services, BelTA state news agency reported.

"They have crossed the line. We cannot forgive them," Lukashenko said at a gathering marking the country's Independence Day.

The veteran leader said Germany, Lithuania, Poland, Ukraine and the United States were behind the alleged rebel activity, BelTA reported.