Since its 1990s inter-ethnic war, Bosnia consists of two semi-independent halves -- the Bosnian Serbs' Republika Srpska (RS) and the Muslim-Croat Federation.

The two entities share weak central institutions while each has its own government, parliament and police. However, the country has a joint army.

Bosnian Serb President Milorad Dodik, regularly accused of separatist aspirations, on Monday confirmed the purchase of the rifles.

"We are witnessing that Republika Srpska president is working on establishing some sort of armed formations," RS vice-president Ramiz Salkic, of the main Muslim SDA party, told Vijesti.ba news portal on Tuesday.

According to Bosnia's constitution, each entity must have two vice-presidents from other ethnic groups than the president, meaning that RS has a Muslim and a Croat vice-president.

"Are they (rifles) for special police? If that's the case it is too much, enormous," the Muslim-Croat entity's Interior Minister Aljosa Campara, also of the SDA, told reporters.

The weapons, ordered from a Serbia's arms factory last October, should arrive in RS in March.

Dodik told reporters that the purchase was "nothing more than the modernisation of police and strengthening of its role".

A month ago Bosnian intelligence authorities said they were investigating media reports that a pro-Russian paramilitary unit has been set up with Dodik's approval.

Dodik firmly rejected the claims.

On Tuesday he said that the questioning of the arms purchase was aimed at "shifting the attention from fundamental security problems" which are, according to him, "presence of jihadist fighters in Bosnia".

Once a darling of the west, the Bosnian Serb strongman now shows more sympathies for Russian President Vladimir Putin.

Bosnia's 1992-1995 war between its Croats, Muslims and Serbs claimed some 100,000 lives.

A half of the country's 3.5 million citizens are Muslims, a third are Serbs, while Croats make some 15 percent of the population.