Germany checking if Merkel's plane woes had 'criminal' cause

German investigators are checking whether there was any criminal cause behind the malfunction of a plane carrying Chancellor Angela Merkel to the G20 summit in Argentina, German newspaper Rheinische Post reported on Friday, citing security sources.

Merkel was on her way from Germany to the summit when the government's Airbus A340 made an unscheduled but safe landing at Cologne-Bonn airport late on Thursday.

Merkel called the incident a "serious malfunction". She and German Finance Minister Olaf Scholz were due to resume their travel to Buenos Aires early on Friday, but they will arrive after G20 leaders start their discussions.

Rheinische Post, citing security sources, said the government was checking whether the incident had a "criminal background", though the sources added that investigators would typically look "in all directions" after such an incident.