Tensions in the Greek town of Idomeni intensified this week after Balkan countries dramatically limited the number of migrants and refugees who can cross their borders. Now, international aid organization Doctors Without Borders, also known as Médecins Sans Frontières or MSF, warns that the bottleneck is placing new strains on the NGOs working at the Greece-Macedonia border to provide aid to the thousands of migrants and refugees stranded there. "This very moment, over 11,000 refugees -- mainly from Syria and Iraq -- are stuck here, and the situation is overwhelming," MSF communications manager Vicky Markofela told HuffPost Greece. Thousands of migrants and refugees are arriving in Greece every day from countries in Africa and the Middle East, hoping to continue on to northern Europe. Up until recently, Macedonia allowed Syrians, Afghans and Iraqis to cross the border from Greece, but the country reversed that decision last month and now allows only a handful of Syrians and Iraqis across each day. As a result, up to 30,000 migrants and refugees are now stuck at the border, up to 12,000 of them living in a makeshift camp in Idomeni that only has the capacity for 2,000 people, according to Greek officials. Greece’s migration minister said that he expects the overall number of migrants and refugees stranded in the country to increase to 70,000 this month. Frustrated with what seems a hopeless situation, many migrants and refugees staged protests near the border last week -- and have attempted to break through border fences that keep them from crossing into Macedonia. On Feb. 29, Macedonian police responded with tear gas to disperse the demonstrators. According to Reuters, at least two people collapsed as a result. Markolefa says she witnessed women holding their children in tears that day, afraid that the tear gas would be poisonous -- or worse, fatal. > We have treated more than 100 patients who have been victims of > police violence. > Vicky Markofela, Doctors Without Borders Tensions between migrants and security forces have been dangerous for some time, Markolefa said. MSF has been treating refugees and migrants for injuries caused by police, including a 6-week-old infant, the organization said on Twitter. “We have treated more than 100 patients who have been victims of police violence, and we have recorded more than five cases where people were attacked by dogs unleashed by Macedonia police," Markolefa said. > This little girl is one of the many we treated following the tear > gassing at #Idomeni. The youngest was 6 weeks old. > pic.twitter.com/7WzXJAtJ4D > — MSF Sea (@MSF_Sea) February 29, 2016 The overcrowding at the camp has also led to massive shortages. Around 1,500 migrants and refugees lack tents and must sleep out in the cold with blankets, Markolefa said. "The queue for food is more than 150 meters long," she added. "All the weight for feeding and helping these people has fallen on NGOs. The authorities stick with documenting them." According to Markolefa, many refugees and migrants in Idomeni are burning whatever they can find to keep warm. Respiratory infections are spreading, she said. Cases of physical and psychological trauma are also on the rise. Facing its own social and economic crisis, the Greek government has been struggling to help the thousands of people arriving on its shores each day. Thanks to E.U. pressure, Greek authorities are stepping up efforts to register people entering the country and temporarily accommodate them, but international and volunteer organizations are still carrying out much of that work. MSF is calling for an immediate solution from the E.U. "We want to strongly express our concern for the health of those people who feel helpless and are in desperate need for safety," Markolefa said. Panagiotis Rigas, another MSF employee, offered a bleak analysis: "This situation is unacceptable both for Greece and the E.U. It is impossible to sustain our infrastructure." _This post first appeared on_ HuffPost Greece. It has been translated into English and edited for clarity. -- This feed and its contents are the property of The Huffington Post, and use is subject to our terms. It may be used for personal consumption, but may not be distributed on a website.