After a letter bomb exploded in the Ukrainian embassy in Madrid on Wednesday, leaving one person slightly injured, the Spanish government also announced that it had received a dangerous shipment.

A letter bomb addressed to Prime Minister Pedro Sánchez was received on November 24 and rendered harmless, the interior ministry said. In addition, a similar shipment was received by the weapons manufacturer Instalaza in Zaragoza late on Wednesday evening. The company produces weapons of war that Spain supplied to Ukraine.

A fourth suspicious shipment was intercepted early Thursday morning at the Torrejón air force base near Madrid. From there, military planes take off with supplies for the Ukraine. This package is currently being investigated by the police. “The scanner showed that there was a suspicious mechanism in it,” said a spokeswoman for the Ministry of Defense of the German Press Agency.

The Spanish authorities did not rule out that all four programs could be related to the war in Ukraine. The investigations are based on terrorist attacks. Ukrainian Ambassador Serhiy Pohoreltsev suspected Russia was behind the attack on the embassy.