SARAJEVO (Reuters) - Police in Bosnia and Croatia detained more than 20 people on Tuesday suspected of being part of a criminal ring that has smuggled up to 200 migrants into the European Union, Bosnia’s state prosecutor said.

The group, suspected of transporting, hiding and smuggling migrants mostly from Turkey via Bosnia, EU member Croatia and further on to Western Europe, has been monitored by the police since the start of 2018, the prosecutor said in a statement.

The investigation showed that the ring organizers, who are nationals of Turkey and Kosovo, charged migrants more than 10,000 Bosnian marka ($6,257) each to take them to EU member states, the office said.

Those detained also include 11 Croatia nationals and one Bosnian, the Croatian police told local media.

The so-called Balkan route for migrants trying to reach the EU via Turkey, Greece and former Yugoslav countries was shut down in 2016 when Turkey agreed to stop the flow in return for EU aid and a promise of visa-free travel for its own citizens.

Until recently, the few still making the journey had avoided mountainous Bosnia, some of whose citizens themselves became refugees in Western countries after its devastating war in the 1990s.

But the impoverished Balkan country, which has a 1,000 km border with EU member Croatia, has lately emerged as an alternative migrant route starting from Turkey via Greece and Albania through Montenegro, as well as for those stuck in Serbia.

The authorities said this week that 1,139 migrants mostly from Syria, Pakistan, Libya and Afghanistan have entered Bosnia since the start of 2018 and almost as many were intercepted at the borders.

They warned that Bosnia cannot cope with a steep increase in the number of migrants expected with warmer weather. The country has only one center for asylum seekers and another one for illegal migrants, both of which are full.

Volunteers, helping the migrants with accommodation and food, say their numbers are double the official estimates.

They say the government is failing to adequately protect the rights of refugees who lack food, shelter and medical care. The Bosnian Islamic Community has also called on authorities to do more to meet the basic needs of refugees.