SUBOTICA, Serbia (Reuters) - Serbia has sent special forces to the border with Hungary as hundreds of migrants a day try to reach the European Union.
With Serbia on the main route for refugees from Asia, Africa and the Middle East, mainly coming through Turkey, the police have long been at the border.
But they have now sent in more heavily armed personnel after what an NGO said were turf wars among criminal gangs and a police chief said were conflicts among migrants.
On Tuesday, police said they detained 371 migrants along the border. Two men were detained in a tent, and dozens including a family with two children were gathered in a field, Reuters footage showed.
They also detained several people found up trees who they suspected of acting as scouts keeping a look-out for other migrants, Dragan Vasiljevic, deputy director of the Serbian police, told Reuters.
Migrants in the area typically try to use ladders to clear the border or cut the fence.
"Bearing in mind developments in recent days when there was a conflict and some people sustained injuries, a big police action was conducted," Vasiljevic said.
"We have found some weapons, notably four automatic rifles. For the first time we have found a number of migrants hiding in the trees."
According to numbers from Serbian NGO the Centre for Asylum Seekers, some 1,500 migrants attempt to cross into Hungary every day - many handing over cash to people smugglers.
"What our field workers see is that they all cross the border eventually and move on (to the EU). The question is only how much they will have to pay for that," Rados Djurovic, from the Centre for Asylum Seekers, told Reuters.
"We have seen a rising number of armed incidents involving migrants," Djurovic said adding that the incidents involved various criminal groups "fighting for territory".
According to official figures, there are some 3,326 migrants in government reception centres, but may are not accommodated in the centres and can be seen on the streets of the capital Belgrade and also along the 175 km border with Hungary.
(Reporting by Branko Filipovic in Subotica and Ivana Sekularac in Belgrade; Editing by Alison Williams)