Security members protect Venezuelan President Nicolas Maduro after his speech was interrupted in Caracas, Venezuela, on Aug. 4, 2018. File image: Xinhua.

Caracas - Venezuela's intelligence service has arrested an opposition lawmaker who President Nicolas Maduro says was involved in a drone attack against him, the lawmaker's Primero Justicia (PJ) party said Wednesday.

Juan Requesens and his sister, Rafaela, were detained in their Caracas home late Tuesday, the PJ reported on Twitter.

Rafaela Requesens was later released.

"I hold the regime of Nicolas Maduro responsible for what may happen to my brother and my entire family," she tweeted.

Juan Requesens' arrest had earlier been mentioned by opposition leader Julio Borges, whom Maduro also accused of involvement and who is out of the country.

The PJ accused Maduro of "political persecution" of the opposition.

Another opposition leader, Henri Falcon, has expressed concern that the investigation into Saturday's attack could turn into a "witch hunt" for opposition leaders.

Six people were earlier arrested on charges of being the executors of the alleged attack, in which drones carrying explosives went off in front of Maduro as he spoke at a military ceremony in Caracas on Saturday.

The president was unharmed, but seven soldiers were reported to have been injured.

Colombia's former president, Juan Manuel Santos, who handed over office to his elected successor Ivan Duque on Tuesday, has rejected accusations by Maduro that he was involved in the attack.

Maduro, who has presided over a rapid decline in his country's economic fortunes, was re-elected to another six-year term in May. The poll was denounced as undemocratic by the European Union, the United States and at least 12 Latin American countries.

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