It was the first time that police found weapons with migrants who have been passing through the Balkan country in growing numbers since the start of the year as they head towards western Europe.

"For the time being we do not know what they were planning to do with (the weapons)," a police spokeswoman told AFP.

"The two men tried to flee when police asked them for documents but they were quickly arrested," spokeswoman Suvada Kuldija said.

The arrests were carried out on Sunday evening.

Police searched several locations linked to the two where they found and seized a "rifle, four guns, a silencer and more than 100 bullets of different calibres," the spokeswoman added.

The 34-year-old Syrian national was officially registered with the authorities in charge of migrants, while police were verifying the status of the 23-year-old Algerian.

Since the start of the year, 15,000 migrants trying to reach western Europe have been registered in Bosnia, a minister said Sunday.

So far the influx does not compare with the hundreds of thousands who arrived in Europe via the 'Balkans Route' in 2015 and 2016, fleeing war and poverty across Africa and the Middle East.

The route was effectively closed in March 2016.

Now, most of the migrants, who enter Bosnia from Serbia or Montenegro, stay for a few days in Sarajevo before heading towards the northwestern town of Bihac.

Bihac is on the border with Europan Union member Croatia, where they try to sneak into the bloc.

Since the 1990s wars that marked the collapse of Yugoslavia, the Balkans have been considered a centre for arms trafficking.

Jihadists who have carried out attacks in western Europe in recent years are also believed to have passed through.