If Russia is proved to be behind an incendiary device plot that caused fires at two parcels warehouses in July, it will be evidence that Moscow is aiming to disrupt western confidence, an expert has said. The dangerous packages, which caught light at DHL sites in Birmingham and Leipzig, are not thought to have been sophisticated but in both cases appear to have evaded security checks. German authorities warned this week that a plane could have been downed if the devices, which were both sent by air, had ignited in flight. Brandon Fried, executive director of the Airforwarders Association, which represents the air freight industry in the US, described the incendiary bomb incidents as disconcerting given the suspicion of Russian state involvement. “It looks like the goal is simply to disrupt the supply chain, create havoc and simply to scare people. They want people to lose confidence in the system,” Fried said, adding that the industry had developed robust and evolving security procedures since 9/11. Counter-terror police in Britain are investigating whether the Birmingham incident is linked to the one in Leipzig, amid a strong belief that the incendiary devices were the work of Russian spies. The parcel that ignited at a DHL warehouse in Birmingham on 22 July appears to have travelled by air before reaching the UK. Nobody was hurt and the incident, first reported by the Guardian, was dealt with by fire crews and staff. The German package started burning as it was about to be loaded on to a plane at Leipzig at the end of July, German media has reported, and the head of the country’s domestic intelligence service warned on Monday it could have brought down an aircraft. Security sources said questions about how the packages got on to DHL sites were a question for the courier company, given the security procedures that exist at airports to prevent explosives and devices that can cause fires getting on to planes. DHL said in a statement on Thursday that it employed “stringent security and safety measures throughout our global network” and that it worked “in full compliance with all applicable laws, regulations and procedures”. German authorities issued a warning at the end of August of “unconventional incendiary devices” that appeared to have been dispatched by private individuals, which “caught fire … in several European countries”. They said there could be further attacks in an effort to damage logistics across Europe. Intelligence agencies across Europe have been warning of a growing number of arson, sabotage and even murder plots being carrying out by Russian intelligence in an attempt to sow discord among western backers of Ukraine. Last week, Ken McCallum, the head of MI5, warned that Russia’s GRU military intelligence appeared to be on “a sustained mission to generate mayhem on British and European streets” and accused the Kremlin of being engaged in “dangerous actions conducted with increasing recklessness”. Incendiary devices are generally considered to be relatively unsophisticated compared with explosives, so constructing them may not have required a high level of technical knowhow. The suspect packages that had been found so far all contained either electrical items or containers with liquids, according to German investigators.