Bulgaria’s parliament on Wednesday granted the army greater powers to help guard the country's borders, amid fears the migrant flow along the Balkan route will pick up with the onset of warmer weather.
Until now, troops have only been able to provide border forces with technical and logistic support.
Following Wednesday's vote, the army can now carry out joint patrols with border police in crisis situations such as increased migrant pressure along the borders.
EU member Bulgaria already has close to 2,000 police guarding its porous 260-kilometre (160-mile) frontier with Turkey and is currently extending a 30-kilometre razor-wire fence.
The measures have helped the country remain on the sidelines of the major migrant route from Turkey and Greece to northern Europe.