A bipartisan group of U.S. lawmakers is urging the head of the U.K.’s surveillance court to conduct an open hearing regarding Apple’s expected challenge to an alleged secret U.K. government demand.

This week, U.S. Senator Ron Wyden, joined by four other federal lawmakers, wrote a letter to the president of the U.K.’s Investigatory Powers Tribunal (IPT), stating that it is in the public’s best interest for any hearings related to the alleged order to be held transparently and not in secret.

The lawmakers’ letter also asserts that the alleged U.K. order has restricted California-based Apple from exercising speech that is protected under U.S. law and hinders the lawmakers’ ability to carry out congressional oversight.

As reported by The Washington Post in February, the U.K. government had earlier this year secretly ordered Apple to create a backdoor that would allow U.K. authorities to access the cloud-stored data of any Apple customer worldwide. Apple, which is legally barred from discussing the so-called “technical capabilities notice,” reportedly declined to comply with the order and instead withdrew its Advanced Data Protection iCloud data-encryption feature for U.K. customers.

The U.K.’s Investigatory Powers Tribunal, responsible for hearing cases related to the use of U.K. surveillance powers, is set to hear a private petition on Friday, according to the tribunal’s public schedule. The hearing is reportedly related to Apple, as stated in Wyden’s letter.

When contacted by TechCrunch on Friday, Apple declined to comment.

The U.K. government has so far declined to comment on operational matters, including confirming or denying the existence of any such notices, according to a spokesperson.

The number of companies that have received a technical demand from the U.K. government remains unclear.

According to the lawmakers’ letter, Google informed Senator Wyden’s office that, if it had received a technical capabilities notice, it would be prohibited from disclosing that fact.

Two civil rights groups, Liberty and Privacy International, are also challenging the U.K. government’s backdoor order through a legal submission to the IPT. The pair has also called for the oversight body’s hearing into Apple’s appeal to be held in public, joining similar calls made earlier this week by privacy rights groups.