CARACAS – Venezuelan authorities arrested eight Colombians, one of them identified as a “paramilitary chief,” and two Venezuelans in a western border city while they were distributing pamphlets with threatening messages for local businessmen.

Interior Minister Tarek El Aissami, in an interview with state-run VTV television, identified the presumed militia leader as Jorge Roa Bolaños and said that he and the other nine detainees were caught red-handed in San Antonio del Tachira, a city 850 kilometers (528 miles) west of Caracas.

Different reports surfaced about the number of establishments shuttered in that city on Friday, with local media indicating as many as a thousand kept their doors closed while the interior minister said just a “limited number” were not open for business.

“However, once we strengthened the (military and police) presence, little by little calm was restored and daily activity” resumed in San Antonio, El Aissami said.

Both military authorities and the regional heads of the Fedecamaras national business federation concurred that paramilitaries were behind the threats that disrupted commercial activity Friday in the city.

It was unclear whether the threats were related to the recent killings of 11 people – nine Colombians, a Peruvian and a Venezuelan – who had been kidnapped from a soccer field in the same area.

The region bordering Colombia is one the most violence-ridden areas of Venezuela, according to authorities, who say that Colombian guerrillas, militiamen, drug traffickers and kidnapping gangs are all active there.

Relations between Colombia and Venezuela have deteriorated in recent months, with Bogota accusing its neighbor of arming Colombian leftist rebels – labeled as terrorists by Bogota, Washington and the European Union – and Venezuela irked over those accusations and a deal signed this week that gives U.S. troops access to Colombian military bases.

Chavez, survivor of a 2002 coup attempt that former U.S. President Jimmy Carter says took place with Washington’s advance knowledge if not active collusion, says the basing agreement poses a threat to his “Bolivarian Revolution.”

Venezuela’s socialist government, meanwhile, on Thursday presented in Caracas what officials called “irrefutable evidence” that neighboring Colombia has dispatched spies to Venezuela, Ecuador and Cuba as part of an ambitious, CIA-financed operation.

El Aissami detailed the contents of documents allegedly originating with Colombia’s DAS security service and unearthed since the apprehension of two suspected Colombian on Venezuelan soil.

Caracas obtained the documents pursuant to the capture of two DAS agents in Venezuela, El Aissami told the National Assembly.