A man uses phone under a Volkswagen logo at the Shanghai Auto Show, in Shanghai, China April 20, 2017. REUTERS/Aly Song

MUNICH (Reuters) - Searching the offices of Volkswagen's VOWG_p.DE law firm was not illegal, a German regional court said on Monday, prompting the carmaker to say it would lodge an appeal with Germany's Federal Constitutional Court.

In March, Munich prosecutors searched the offices of Jones Day, a U.S. law firm hired by Volkswagen VOWG_p.DE to investigate its emissions scandal, stepping up efforts to identify those involved in Volkswagen's emissions-test cheating scandal.

Volkswagen, Europe’s biggest carmaker, has condemned the search and filed a legal complaint.

It said on Monday it would now take the matter to Germany’s highest court, the Federal Constitutional Court.

“The Munich regional court’s decision in now way gives us reason to change our legal position,” it said in an e-mailed statement.