This article originally appeared in The Financial Times

Ukraine’s $23bn debt restructuring negotiations appeared to reach boiling point late on Tuesday after the government issued a sharply worded statement that questioned the transparency, responsiveness and good faith of a creditors’ committee.

With positions hardening weeks before a planned June deadline to avoid default, the finance ministry of war-torn and recession-battered Ukraine in the statement said it was “concerned about the approach taken by the creditors’ committee representing the country’s external debt holders and their lack of willingness to engage in negotiations.”

Claiming that the creditor committee refused “despite numerous requests” to reveal its membership, the finance ministry stressed that it and debtholders needed by June “to agree on a sustainable debt level and debt service objectives meeting the targets” of an International Monetary Fund programme granted earlier this year.

“The ministry is committed to transparency, responsiveness and good faith negotiations and expects the creditors’ committee to do the same,” Kiev added.

The tough words come amid increasing market expectations that the restructuring talks are likely to stretch on through the summer as Ukraine continues — in the face of creditor disapproval — to demand a haircut, cuts to the coupon and maturity extensions to free up $15bn over the next four years.

Reaching that target is part of a broader $40bn assistance program that includes a $17.5bn IMF loan and some $7.5bn in bilateral assistance.

Negotiations between international investors and the government appear to have reached deadlock, with a group of the country’s largest investors declaring earlier on Tuesday that they were “ready and willing to support a prudent debt restructuring with Ukraine” but had had “no substantive engagement” from the government.