Greek Prime Minister Alexis Tsipras criticised Macedonia for using “excessive force” after police fired tear gas and rubber bullets on refugees trying to breach the closed border to enter the EU. He referred to the issue as a "disgrace" for Macedonia.
Macedonian police accused refugees of throwing stones and other objects at them on Sunday in order to break down a fence at the border with Greece, saying they had used tear gas to “protect” themselves.
The United Nations' refugee agency UNHCR also condemned Macedonian police on Monday for the use of tear gas against refugees on the border with Greece and said such action damages Europe's image.
"Time and again in recent months we have seen tension unfolding at various European borders, between security forces on the one hand and people fleeing war and in need of help on the other," UNHCR spokesman Adrian Edwards said in a statement.
"People get hurt and property is damaged. Harm is done to perceptions of refugees and to Europe's image alike. Everyone loses."
Doctors Without Borders said 260 people were treated for injuries: 200 for breathing problems, 30 for wounds caused by plastic bullets and 30 for other injuries.
There are approximately 11,000 refugees fleeing from war in Syria and Iraq stranded at the flashpoint Idomeni crossing.
Refugees have been living in rough conditions at the Idomeni camp since Balkan states decided to close their borders to stop the refugee flow in Europe in mid-February.
The spokesman for the Greek refugee coordination agency Giorgos Kyritsis slammed the Macedonian reaction as totally unwarranted and out of proportion.
He told Vima radio station that there had been “an excessive and asymmetrical use of force” that had resulted a “very difficult situation on Greek soil.”
About 300 people were treated on Sunday for injuries according to police.
With only two people remaining in hospital, a police source said on Monday that the situation was “calm” in Idomeni camp.
The Greek government said it had lodged two "very strong protests" with Macedonian authorities.
Kyritsis said Greece had also “launched action against other European countries which have sent police observers to the Macedonian side”, including Slovenia and Hungary.
Tensions grew high in Idomeni on Sunday a day after pamphlets written in Arabic were distributed at the camp that the border would be reopened.
Greek authorities were aware of the tract and had doubled the police presence at the frontier on Sunday.
An official at a refugee centre on the Macedonian side of the border said three 500-strong groups of people had tried to breach the barrier in three different places on Sunday.
The temporary encampment at Idomeni, where people are living in harsh and overcrowded conditions, has become a symbol of the misery faced by thousands who have fled war and poverty to reach Europe.
Efforts by the Greek authorities to persuade refugees to leave Idomeni and move to nearby reception centres have not been successful, with many people preferring to stay put in the hope that the border will be opened.