Berlin police are investigating a possible arson attack after the campaign bus of a party colleague of Chancellor Angela Merkel was burnt to the ground.

The bus belonging to CDU (Christian Democratic Union) party member Thilo-Harry Wollenschlaeger was set on fire in Berlin’s Spandau district on Thursday, local media report.

Police were dispatched to the scene after a driver reported a fire had started at a parking lot on the outskirts of the German capital in the late hours of Thursday night, police reported, according to Der Spiegel. A crane and a tow vehicle parked nearby were also damaged in the blaze. There were no reports of victims.

Merkel’s party ally Wollenschlaeger is running for the upcoming local parliament elections that are to take place on September 18.

The bus was not targeted by coincidence, director of the CDU Berlin office Dirk Reitze said, according to Berliner Zeitung.

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Merkel’s party ally Wollenschlaeger is running for the upcoming local parliament elections that are to take place on September 18.

“The crime scene is located in a very remote area, almost at the city border. They must have gone that far on purpose,” he said.

Wollenschlaeger, who is well-known in the city, uses the bus for his own purposes and sometimes even spends the night there, Reitze told the Local.

“We don't even want to think about what would have happened, had they slept in there," Reitze said.

Frank Hankel, CDU Berlin leader and senator of the Interior and Sports of the state of Berlin, condemned the attack by saying that “it is not acceptable to fight a pre-election battle this way,” according to a CDU Spandau Facebook post.

In an interview with Berlin Zeitung he added that the political debates have reached a new low, with CDU posters already being constantly torn off and burnt on the streets. “The coward arson attack on the CDU campaign bus has a whole new quality,” Hankel said.

Green party candidate Ramona Pop condemned the arson as “an evil attack on the democratic competition and freedom of expression.”

Übler Angriff auf demokratischen Wettbewerb und Meinungsfreiheit! https://t.co/zPHO5xWccz — Ramona Pop (@RamonaPop) August 5, 2016

Attacks on party offices have recently been on the rise in Berlin as the elections move closer. On Sunday unknown attackers shattered windows at an SPD (the Social Democratic Party of Germany) office in the district of Baumschulenweg. On Monday there were reports of a fire at a garage that belonged to the AfD party (the Alternative for Germany) in the eastern Berlin district of Johannisthal.