Austrian authorities have arrested an alleged Islamic extremist suspected of belonging to a terrorist group, German prosecutors said Saturday.

The 26-year-old, identified only as Yusuf O., was detained in Austria in late May on a German arrest warrant, the Federal Prosecutor's Office said. The arrest had not been made public earlier because extradition procedures are still under way.

The German national of Turkish descent is suspected of involvement with the German Taliban Mujahideen, a fundamentalist group that prosecutors say seeks to carry out attacks in Afghanistan and Pakistan and found a "religious fundamentalist society" there. Prosecutors declined to elaborate.

German media reported the suspect underwent paramilitary training in a terror camp in Pakistan's lawless border region and appeared in several Islamist propaganda videos.

On Wednesday, Austrian authorities also arrested four other suspected extremists linked to the German Taliban Mujahideen at Vienna airport on suspicion they were heading off to train at terrorism camps in Afghanistan or Pakistan.

But a spokesman for Germany's Federal Prosecutors Office on Saturday dismissed a report alleging that one of the four suspected extremists was plotting to attack the country's parliament in Berlin with a commercial airplane.

"There are no indications of concrete preparations for an attack in Germany," the official said on condition of anonymity in line with department policy.

Austrian daily Kronen Zeitung reported that 25-year-old suspect had undergone flight training and was plotting to target Berlin's emblematic parliament building by hijacking an airplane.

The newspaper gave no source for its report. Prosecutors in Vienna were not immediately reachable for comment.

German prosecutors said there was no "criminally relevant link" between Yusuf O. and the group of four.

However, the prosecution spokesman added that the group is also under investigation in Germany, though not in connection with a concrete plot but on suspicion of "providing financial support to the violent jihad."

Germany has so far escaped a major terror attack, but several terror plots were foiled in their early stages over the past few years.

In April, German police arrested three suspected al-Qaida members in the western city of Duesseldorf allegedly working on making a shrapnel-laden bomb to attack a crowded place. Authorities believe the cell's alleged ringleader trained in a terror camp in Pakistan.

Germany's domestic intelligence agency, the Office for the Protection of the Constitution, says that about 225 people who are German citizens or have lived in Germany, have undergone paramilitary training in Afghanistan or Pakistan since the 1990s.