Slovakia's government has deployed more than 2,000 soldiers and police officers in Roma areas in an attempt to stop looting and other unrest.
Roma man shows his injuries allegedly caused by police
The decision was taken at an emergency cabinet meeting late on Tuesday.
Hundreds of Roma, protesting against government cuts in welfare benefits, stormed shops and clashed with police since last week.
Roma (or gypsy) leaders have called off nationwide rallies planned for Wednesday to prevent further violence.
An interior ministry spokesman said more than 70 Roma had been arrested so far.
Interior Minister Vladimir Palko has visited the affected areas together with the prime minister.
"This is the biggest transfer of security forces since
1989," Mr Palko said, referring to the mass peaceful protests which led to the fall of communism in the then-Czechoslovakia.
The incidents started with several cases of looting last week in eastern regions. On Monday, hundreds of protesters clashed with police in Trebisov.
Police said there was only one case of looting on Tuesday night, in the central village of Hucin.
The intruders stole coffee, cigarettes, alcohol, frozen food, sausages and other groceries, causing a total damage worth 100,000 koruna (2,463 euros.)
Roma leaders say they cannot tolerate delinquency in the name of their community.
A Roma leader in eastern Slovakia, Frantisek Gulas from the Slovak Romany Council, told the AP news agency that his group was working with police to try to persuade Roma not to loot.
"I am not thrilled that police had to intervene," he said.
"But everybody, including the Roma, have to realise
that laws are here for all and have to be kept."
Slovakia's centre-right government introduced the welfare cuts as part of its efforts to strengthen the economy ahead of EU membership on 1 May.
The cuts hit the impoverished Roma community especially hard.
Correspondents say unemployment rates are high among the Roma, reaching 100% in some villages.
On Tuesday, Slovakia's leftist President Rudolf Schuster warned that the incidents could lead to wider social unrest.
He blamed the government for introducing "untimely and unfair cuts" to welfare benefits.
He has also appealed for calm to the Roma community, who make up more than 8% of the population.