Hundreds of people were injured when Macedonian police fired tear gas on a group of refugees as they tried to break through a fence on the Greece-Macedonia border, the medical charity Doctors without Borders (MSF) said.

"On April 10, after the violent events at the border between Greece and Macedonia, Medecins Sans Frontieres medical teams treated hundreds, including around 40 people injured by rubber bullets. At least 10 people have reported to MSF teams that they were beaten by Macedonian police," MSF said in a press release on Sunday.

Achileas Tzemos, an MSF official, told the Associated Press news agency that the injured included about 200 experiencing breathing problems from the gas, and 100 others with cuts, bruises and impact injuries from non-lethal plastic bullets. He said six of the most seriously injured were admitted to a hospital.

A Macedonian police source said three officers were injured by stones thrown by the protesting refugees. Greek police observed from their side of the frontier but did not intervene.

Clashes continued into the afternoon, and the wind brought tear gas fumes into a nearby makeshift camp on the Greek side of the border holding more than 11,000 stranded refugees.

Many people, including small children, who were not involved in the clashes, were suffering from respiratory problems. Volunteer doctors were treating several dozen refugees with respiratory problems, slight injuries from the plastic bullets and facial injuries from close quarter clashes when the fence was temporarily breached.

Greece said on Sunday that the use of force against refugees was "dangerous and deplorable".

"The indiscriminate use of chemicals, rubber bullets and stun grenades against vulnerable populations, and particularly without reasons for such force, is a dangerous and deplorable act," said George Kyritsis, a spokesman for migration coordinators in the Greek government. 

The clashes began soon after some 500 refugees gathered close to the fence.

Activists had distributed leaflets in Arabic calling for the refugees to gather at the fence on Sunday morning. A delegation of five refugees asked Macedonian police whether the border was about to open.

When Macedonian police denied this, more than a hundred refugees, including several children, tried to scale the fence.

Macedonia and other Balkan countries to its north have shut their borders, closing what was the busiest migrant route to central Europe.

The European Union has since put an end to the hopes of many refugees, saying it would only accept war refugees from Syria and Iraq as well as those from other countries who are eligible for asylum.

Macedonian police sources said police fired only tear gas after migrants stormed a border fence on Sunday [Amel Emric/AP]

Source: Agencies