KHARTOUM, Sudan (CNN) -- Sudanese authorities aborted a plot "to create chaos, target leaders of the country and destabilize the county," in what appeared to be an attempted coup d'etat, Sudan's minister of information told reporters Thursday. 

"The act was planned for last Thursday, then was postponed to this Thursday," Ahmad Bilal Osman said. The government's goal was "to have it aborted before it began, and that happened." 

Earlier in the day, the semi-official Sudanese Media Service had reported that, "according to a source in the National Security (agency), a plan of sabotage was aborted at dawn this morning that aimed to create security chaos which was led by persons from the opposition."

Thirteen people were arrested, according to Osman, most notably Salah Ghosh, former head of Sudan's National Intelligence and Security Services.

Sudanese Media Service said the source added that there was a "plan of sabotage which sought to shake the stability and security of the country," and that after the arrests, "the specialized authorities" immediately began investigations of "civil and military persons connected to the plan."

The apparent coup attempt comes at a time when Sudan is facing serious challenges with conflicts in the country's peripheral provinces of Blue Nile, South Kordofan and Darfur. 

Sudan's oil-dependent economy took a blow in 2011 when South Sudan seceded, taking with it the majority of the oil wealth. Economic austerity measures last summer sparked Arab Spring-like protests against the government, and increased calls for reform within the National Congress Party, led by Sudanese President Omar al-Bashir, who has ruled since 1989.

Witnesses said they saw tanks and military vehicles move around in the capital in the very early morning hours Thursday.

"I saw tanks around one of the bridges," one witness said.

Osman said "things are now stable" and "there is no extension of this act into the army or security" services.

"Some in the opposition dreamt that this chaos would create an opportunity to topple the regime," he said. "They are dreaming."

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