The Iran nuclear program's Arak heavy-water reactor. Photo: Nanking2012/Wikimedia Commons.

British officials have informed a U.N. panel that Iran has continued operating an active procurement network with two blacklisted firms, a confidential report leaked online by Reuters revealed on Thursday.

“The U.K. government informed the Panel on 20 April 2015 that it ‘is aware of an active Iranian nuclear procurement network which has been associated with Iran’s Centrifuge Technology Company (TESA) and Kalay Electric Company (KEC),'” said the report.

In addition, the report stated that certain U.N. member states assessed that Iran has continued to actively pursue nuclear procurement “through circumvention techniques,” calling into question the trustworthiness of the Iranian government ahead of the June 30 deadline for reaching a nuclear deal with Western powers.

It cited reports from an unnamed member state that said an Iranian interest had recently attempted to acquire a key component of the uranium enrichment process under a fake end-user certificate.

Earlier this month, the Washington Free Beacon reported that the U.S. had gathered intelligence of illegal weapons components shipments from North Korea to Iran, but kept the information from reaching the U.N.

KEC is sanctioned under the U.N. Iranian sanctions resolution that was adopted in 2006, while TESA is under U.S. and EU sanctions.

Responding to the report, U.S. Secretary of State spokeswoman Marie Harf told reporters that the U.S. remains “concerned about their [Iran’s] procurement,” according to an AP report.