Ukraine says a number of its European embassies have received “bloody” packages containing animal eyes, including its embassy in Madrid, which also received a letter bomb earlier this week.

Spanish police cordoned off the Ukrainian embassy on Friday and were searching the area with sniffer dogs.

The packages, soaked in a liquid with a distinctive colour and smell, have also been sent to embassies in Hungary, the Netherlands, Poland, Croatia and Italy, to general consulates in Naples and Kraków, and the consulate in Brno in the Czech Republic, said Ukraine’s foreign ministry spokesperson, Oleg Nikolenko.

“We are studying the meaning of this message,” Nikolenko said in a statement on Facebook, adding that the foreign minister, Dmytro Kuleba, has ordered all the embassies and consulates concerned to be placed under heightened security.

Ukrainian officials also said the entrance of the Ukrainian ambassador’s residence in the Vatican was vandalised and that a false bomb threat was received regarding its embassy in Kazakhstan.

The bloody missives follow the reception of six letter bombs sent in the past week to addresses in Spain including Ukraine’s embassy in Madrid, the prime minister, Pedro Sánchez, and the US embassy in Madrid, prompting Spain to step up security.

A Madrid embassy employee was injured after opening a package addressed to Ukraine’s ambassador to Spain on Tuesday. The employee decided to open the package, which was received by normal mail, in the embassy garden because it contained a small box.

“After opening the box and hearing a click that followed, he tossed it and then heard the explosion,” the ambassador to Spain, Serhii Pohoreltsev, told Ukraine’s European Pravda news site. “Despite not holding the box at the time of the explosion, the commandant hurt his hands and received a concussion.”

Spanish police later said a similar package was sent to a Spanish arms company that manufactures rocket launchers Spain has donated to Kyiv, and that they believed the two incidents were linked.

Reuters contributed to this report