Poland and Belarus are engaged in tit-for-tat trade blame on migrants’ crisis and violations of international human rights laws.
Polish police have detained over 50 migrants who crossed into Poland from Belarus over the last 24 hours.
Tomasz Krupa, spokesman for the Podlaskie regional police, told AFP news agency on Wednesday that the arrests were made near Bialowieza village, near Poland's border with Belarus, after "they illegally crossed the border".
Krupa said police were still looking for others, who had evaded detention.
The situation on Poland-Belarus border remains tense as the two countries trade blame on influx of migrants.
"The situation is not calm," Polish Defence Minister Mariusz Blaszczak told Polish Radio on Wednesday, adding that smaller groups of migrants were now attempting to breach the border of the EU and NATO member.
"While two days ago we had one large group concentrated near Kuznica Bialostocka and there was... an attempt to force the border, now we are dealing with smaller groups, although numerous, which are simultaneously attacking the Polish border in several places," he said.
The Polish defence ministry alleged that Belarusian officials were using intimidation to force migrants to breach the border.
It also tweeted two short videos on Wednesday capturing a shot allegedly fired on the Belarusian side of the border by an armed man in uniform.
The videos show a group of migrants standing near border security on the Belarusian side of the border. Among them are children.
In return, the Belarusian Defense Ministry summoned the Polish military attaché to protest what it called “unfounded and unlawful Polish allegations" against the Belarusian military at the border.
It also voiced concern about the buildup of Polish troops there, saying Warsaw did not notify or invite Belarusian observers per international rules for activity involving more than 6,000 troops.
Earlier this week, the Belarusian Foreign Ministry lashed out at Poland, pointing out that the attitude of Poland toward foreigners seeking asylum will become a litmus test of Warsaw's commitment to the principles of international law, humanism, and human rights protection.