The European Union gave Greece a 90-day deadline on Friday to figure out a way to control its borders, or be subject to the possibility of getting stuck with millions of refugees and effectively be removed from the Schengen passport-free travel zone established by the EU decades ago.

The EU announcement on Friday states that Greece has one month to “establish an action plan to remedy the deficiencies … [and] within three months of the same date, it shall report on the implementation.”

“It is of utmost importance that Greece addresses the issues identified in the report adopted by the Commission as a matter of priority and urgency,” EU ministers said.

They added that Greece had to take action on registration procedures, sea border surveillance, border checks, risk analyses, human resources and training as well as equipment and international cooperation.

In a document published on the European Council website, Greece rejected the report’s contention that it was responsible for “serious deficiencies” in border control and denied it was “seriously neglecting its obligations.”

Greece also said it had taken a number of measures at “substantial national financial and social cost” and reminded Brussels that the massive influx on its borders would put any member state under “severe pressure.”