Large groups of migrants are still attempting to illegally cross the Poland-Belarus border, authorities have said.
The Polish Border Guard reported that a group of around 200 migrants tried to force open the border near the village of Czeremcha.
The authority described the migrants as "aggressive" and said that stones were thrown at Polish officials.
A day earlier, the authority said that 100 people had tried to illegally enter Poland near Dubicze Cerkiewne.
A group of 40 migrants reportedly tried twice to illegally enter the EU member state near the village of Mielnik on Wednesday. One soldier was injured in the head and had to be treated medically, a spokeswoman added.
"Aggressive foreigners attacked Polish services by throwing stones, tree branches and stun grenades," the Border Guard said on Twitter.
According to the authority, there were 375 attempts to cross the border fence from Belarus on Wednesday.
Thousands of migrants -- mainly from the Middle East -- have been trying to enter the European Union via Belarus for weeks.
The bloc has accused Belarusian President Alexander Lukashenko of deliberately encouraging illegal migration to destabilise the EU in retaliation against sanctions.
On Tuesday, European Commission President Ursula von der Leyen reiterated the EU was standing in solidarity with Poland, Lithuania and Latvia.
French President Emmanuel Macron echoed von der Leyen during a meeting on Wednesday with Polish Prime Minister Mateusz Morawiecki.
Although the number of migrants at the Polish border has decreased, Warsaw says the situation has not changed.
On Wednesday, Human Rights Watch (HRW) accused both Poland and Belarus of "serious human rights abuses" at the border.
"Belarusian and Polish authorities have an obligation to prevent further deaths by ensuring regular humanitarian access to the people stuck in the border area," the NGO said in a statement.
"While Belarus manufactured this situation without regard for the human consequences, Poland shares responsibility for the acute suffering in the border area," added senior Europe and Central Asia researcher Lydia Gall.
Polish authorities have previously been accused of pushing back migrants towards Minsk and violating asylum rights.
HRW also called on the EU to "start showing solidarity with the suffering and dying victims at the border on both sides".
Aid groups estimate that at least 11 people have died on both sides of the border since the crisis began this summer.
"Our research has shown that Poland's actions are exacerbating the suffering that people are experiencing," said Ben Ward, Deputy Director of HRW's Europe and Central Asia Division.
"We feel that the European Union ought to be focusing more on that, as well as the situation of the Belarus side," he told Euronews.
"The EU hasn't put enough pressure to Poland to open up the secure area around the border to humanitarian organisations."
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