German police on Tuesday detained a 48-year-old man suspected of several acts of sabotage on the national electricity grid.

The man was held near the Weisweiler power station in western Germany, police said, after days of investigations into a series of incidents on the sites of major infrastructure facilities.

Police launched a manhunt for the 48-year-old after he sent letters claiming responsibility for the attacks to media outlets and authorities. His motive was reportedly climate-related, with the letters criticizing electricity production from fossil fuels.

German Interior Minister Alexander Dobrindt has called the incidents a case of "climate terrorism." In the three German states affected by the incidents – North Rhine-Westphalia, Brandenburg and Saxony – coal is still being mined and used to generate electricity.

The suspect is alleged to have used explosive launching devices to drape a thin wire across high-voltage power lines, thereby causing a short circuit at two locations last week. No power cuts were reported.

Several devices designed to cause explosions were discovered on a high-voltage power line near the Weisweiler power station on Monday, close to the spot where police were subsequently able to arrest the man. Investigators also found another letter claiming responsibility.

The 48-year-old is under investigation on suspicion of causing an explosion involving explosives and disrupting public services.

"The arrest of the suspect is an important step in the investigation," said Brandenburg police chief Oliver Stepien. "The priority now is to further clarify the background and context of the offences and to carefully assess the findings."

According to the police, the man was in possession of explosives at the time of his arrest.

"The items are currently being examined by a bomb disposal expert from the North Rhine-Westphalia State Criminal Police Office," the Cologne police said.

In addition, emergency services found a tent in the undergrowth near the Weisweiler power station which had been fitted with further explosive charges. The man did not resist arrest.

In Saxony, police saying on Monday that at least 21 devices homemade explosive devices have been found and defused.

"These devices were intended to cause damage to the high-voltage power lines by short-circuiting them," the Dresden police and public prosecutor's office stated, adding that no damage to the power grid occurred.