Lithuania on Wednesday allowed in five Afghan asylum-seekers, in a reversal after days of refusing them entry, but insisted a European court order protecting the five on human rights grounds must not be used to establish "a channel" for illegal migration.

Lithuania had sent the five back to Belarus last week in defiance of the European Court of Human Rights, which had prohibited their expulsion and argued they were vulnerable after the Taliban takeover in Kabul and were seeking international protection.

The migrants were detained in Lithuania on Tuesday after they entered once again.

"Due to the European Court of Human Rights decision, many details are unclear. We need an investigation," Border Guard Chief Rustamas Liubajevas told reporters, explaining the turn-around. He said the Guard was "in a very difficult situation."

Lithuania has been pushing back migrants since early August and only a few dozen have been allowed in.

Lithuania's lawyer at the court, Karolina Bubnyte, asked it to remove the protection, calling it "an attempt to use Lithuanian commitments to protect human rights for opening a channel into our country".

More than 4,100 migrants from the Middle East and South Asia have entered Lithuania this year and the EU has accused Belarusia of sending them in retaliation for sanctions imposed by the bloc. Belarus said it would no longer stop the migrants after the sanctions.

(Reporting by Andrius Sytas in Vilnius, Editing by William Maclean)