Poland will extend the implementation of a buffer zone on its border with Belarus for 90 days, the interior ministry said on Tuesday, adding that the measure had been effective in reducing illegal migration.

Prime Minister Donald Tusk's pro-European coalition government reintroduced a no-go zone on a 60-kilometre (37 mile) stretch of the border in June after a surge in attempts by migrants to cross and a string of violent incidents, one of which resulted in a soldier being killed.

The border has been a flashpoint since migrants started flocking there in 2021, after Belarus, a close Russian ally, reportedly opened travel agencies in the Middle East to offer a new unofficial route into Europe - a move the European Union said was designed to create a crisis.

"The zone has brought concrete, positive results," Interior Minister Tomasz Siemoniak said in a statement. "It is primarily aimed at people smugglers who pick up people who are smuggled across the border."

The interior ministry said the number of attempts to cross the border illegally had fallen by 64% since the zone was introduced. The extension will come into effect on Wednesday.

Human rights organisations have criticised the policy, saying it impedes efforts by aid workers to help migrants, including women and children, trapped on the border.

Poland's nationalist opposition Law and Justice (PiS) party accused the government of hypocrisy for introducing a buffer zone after having criticised the policy while in opposition.

Tusk said on Tuesday Poland needed more support in its efforts to secure the eastern frontier, as he criticised a German decision to tighten controls on its land borders.