Venezuela's attorney general ordered the arrests on Wednesday of three government opponents wanted for questioning over an alleged plot to assassinate President Nicolas Maduro. The men include a former presidential candidate and a former state oil company executive.

In an interview with state television, Attorney General Luisa Ortega Diaz said arrest orders were issued for former candidate and United Nations ambassador Diego Arria; Pedro Burelli, the former external director of Petroleos de Venezuela; and Ricardo Koesling, an attorney who has been a strong critic of the Maduro administration.

Ortega Diaz charged that groups are seeking to destabilize Venezuela's government and have formed "violent political plans" against Maduro and other high-ranking officials. Authorities investigating the alleged plot had summoned the three men to appear as witnesses.

Because the three men being sought are believed to be out of Venezuela, authorities plan to ask Interpol to help capture them, Ortega Diaz said.

Burelli, who has lived in the United States for several years, responded with his Twitter account, saying Ortega Diaz "is going down the wrong road". He told the newspaper El Universal earlier this week that he is working with his lawyer to prove that the accusations "are based on forged e-mails".

The attorney general's office opened its investigation in March after officials claimed a plot was being formed against the government. Caracas Mayor Jorge Rodriguez said last month that there was a "complex plan" to topple and assassinate Maduro and other leaders. He accused a former opposition congresswoman, Maria Corina Machado, of involvement and showed e-mail messages that she allegedly shared with government opponents. Investigators have ordered Machado to appear to answer questions on Monday.