A series of suspicious packages sent to Ukrainian embassies this week all had a German shipping address, Kyiv has claimed.
Ukrainian Foreign Minister Dmytro Kouleba said the parcels each had a shipping address of a Tesla car dealership in Germany.
"In the last two days, suspicious packages have arrived at embassies in Italy, Poland, Portugal, Romania, and Denmark, as well as consulates in Gdansk," he wrote on Facebook.
"In total, we already have 31 cases in 15 countries," he added.
"All envelopes are noted the same address of the sender; a Tesla dealership in the German town of Sindelfingen."
The parcels were all sent from post offices that were not equipped with video surveillance, and there were no traces of DNA, the foreign minister said.
Last week, a Ukrainian embassy employee in Madrid was slightly injured after a letter bomb exploded.
Four other explosive packages were sent to addresses in Spain, including to an arms manufacturer and Prime Minister Pedro Sánchez.
Since then, dozens of Ukrainian consulates and missions have reported receiving "bloody" envelopes containing "animal eyes". No one has claimed responsibility for sending the packages.
Kyiv has ordered for security to be reinforced at all its embassies and has denounced the packages as a "planned campaign of terror".
"The threats against our diplomats continue to pour in," Kuleba said on Wednesday.
"The campaign of terror against Ukrainian diplomats, which is currently taking place, is unprecedented on its scale not only in the context of Ukraine but globally," he added.
"No matter how hard the enemies try to intimidate Ukrainian diplomacy, nothing will work in them. We continue to work for victory."