Bulgaria said Saturday it was ready to boost patrols and finish a fence along its southeastern frontier with Turkey in an effort to hold off any new influx of migrants.
The pledge comes as Turkey is in separate rows with Bulgaria and the EU, raising worries Ankara could allow a rush of asylum seekers across the border.
"We are ready to protect the country's border in the way provided for in our legislation," Bulgaria's Defence Minister Stefan Yanev said on a visit to the border town of Malko Tarnovo.
Bulgaria is angry at Turkey's open support for Dost, a party for the ethnic Turkish minority, which is running in the Bulgarian general elections for the first time.
The government in Sofia summoned Turkey's ambassador and recalled its own envoy from Turkey for consultations on Thursday.
Sofia slammed Ankara for encouraging Bulgarian citizens living in Turkey -- who number some 200,000 -- to vote for Dost. It called the move "direct interference in Bulgarian domestic affairs".
Ankara has also been locked in a wider row with the European Union after several bloc members prevented Turkish ministers from holding rallies ahead of the April vote on boosting President Recep Tayyip Erdogan's powers.
As a result, Ankara has threatened to scupper a 2016 deal with the EU to brake the flow of migrants entering the bloc.
This could become a major problem for Bulgaria, which shares a 270-kilometre (165-mile) border with Turkey and would be on the frontline of a new migrant wave.
"The aim of our visit is to inspect the new protective barriers and assess and update the plans for protecting the border," Yanev said Saturday.
Bulgaria had already built over 200 kilometres of razor-wire topped fences to halt an influx of Syrian, Afghan and other migrants last year and Yanev said Saturday that another 24 kilometres of barriers would be ready by May.
Several hundred border police and an additional 200 army officers were also dispatched to patrol along the frontier even if migrant numbers registered a sharp drop compared to last year, he added.