WASHINGTON, April 8 - The International Monetary Fund said on Wednesday it is "vital" that Ukrainian authorities reach agreement with their creditors by June, when the fund's next review of the country's $17.5 billion bailout is due, Reuters reported.

Ukraine officials have set themselves a June deadline to complete a debt restructuring needed to plug a $15 billion funding gap in the IMF program, but many analysts are skeptical that deadline can be met.

"It is vital that Ukraine and the creditors reach an agreement in line with our three criteria and to do so before our review," IMF spokesman Gerry Rice said in a statement. "We want and expect that outcome."

The IMF could only lend to Ukraine under the assumption that its debt is "sustainable," and Kiev can eventually pay back the fund and resolve its balance of payments problems.

In order to do so, Kiev must satisfy the IMF's three requirements for debt talks: generate $15 billion in funds, bring the ratio of debt to annual gross domestic product down below 71 percent by 2020, and make sure the country's financing needs stay at an average of 10 percent of GDP from 2019 to 2025.

The agreement with creditors "will be an important consideration in the upcoming review as we need financing assurances to be satisfactory in order to proceed," Rice said.

The IMF is slated to review Kiev's progress with the bailout conditions in mid-June.

But Kiev may have difficulties meeting all the IMF's criteria. Some creditors have balked at the government's restructuring proposals, including agreeing to write off some debt and accepting lower interest rates or a longer repayment period.

As part of its IMF bailout, Ukraine must comply with a slew of conditions to get its economy in better shape, including strengthening public finances, repairing bank balance sheets and shaking up its energy sector.

It must do so amid continued uncertainty over its territorial integrity. The government in Kiev struck a ceasefire with pro-Russia separatist rebels eastern Ukraine two months ago, but fighting has continued almost daily.

The IMF itself has admitted that efforts to restore Ukraine's financial stability face "exceptionally high" risks, including from creditors balking at the terms of the debt restructuring.

Russia holds a $3 billion eurobond of Ukrainian debt coming due in December, and has said it would not be part of the private sector restructuring. And Kiev may have difficulties persuading all bondholders to agree to write off some debt and accept reduced interest rates or a longer repayment period. (rt/ez)