She said “public safety overriding” exemptions could be used by member states to damage environments protected under the EU Habitats Directive.

Johansson did not explicitly support the wall, instead noting that Poland must prove there is no alternative – and compensate for the environmental impact.

Poland is spending 353 million euros on the 5.5m high wall, which it says is needed to prevent Belarus from sending people from countries like Afghanistan and Iraq.

Tens of thousands of people, including women and children, attempted to cross last year.

Many have been and continue to be illegally deported to Belarus. According to the International Organization for Migration, at least 22 people died in the attempt last year.

Others were held in asylum centers, some of which went on hunger strike given the conditions.

Poland has also banned journalists and aid agencies from entering a so-called exclusion zone near the Belarusian border.

Residents who live near the area risk fines and long prison terms if caught helping people lost in the woods.

Dragging foot

Johansson’s statements are also likely to anger environmentalists and academics who in early February called on the commission to act.

The wall crosses Natura 2000 protected areas. This includes the Bialowieza Forest, a Unesco World Natural Heritage Site.

Bialowieza is a primary forest that extends over some 141,885 hectares and is home to 12,000 animal species, including the largest population of bison in Europe.

Although construction began in early January, it took until the end of April for the Brussels executive to send a letter to Warsaw demanding that the wall comply with EU environmental legislation.

“As soon as the Polish government sends us a response, we will update you on this important issue,” Johansson told the European Parliament plenary session in Strasbourg on Thursday.

But MPs accused the commission of dragging its feet on the issue, given that the wall is already nearing completion.

“The commission says the situation is complex and requires analysis. We heard the same when the rule of law was violated in Poland and Hungary,” said Polish Green MEP Sylwia Spurek.

Criticism also came from the centre-right European People’s Party (EPP).

Speaking on behalf of the group, Polish MEP Elżbieta Katarzyna Łukacijewska said the wall was useless as it would not stop people trying to enter elsewhere.

Journalists can enter Ukraine where they risk being killed, but not in the Polish exclusion zone “for their safety”, she said.

“It raises many doubts and ambiguities,” she said.

Others in Poland are also critical of the wall, including Terespol regional president Krysztof Iwaniuk, who also lives in a town of the same name that straddles the Belarusian border along the Bug River.

“I don’t understand this wall. It gives me chills,” he told EUobserver in a recent interview, noting that he helped bring down the Berlin Wall as a youth.