Spain has stepped up security at public and diplomatic buildings after a spate of letter bombs, including one sent to Prime Minister Pedro Sanchez and another to the Ukrainian embassy in Madrid, where an official suffered minor injuries.

The Interior Ministry revealed on Thursday that an “envelope with pyrotechnic material” addressed to Sanchez had been received on Nov. 24 and disarmed by his security team.
The device was “similar” to packages subsequently received by the Ukrainian embassy and a Spanish arms firm on Wednesday, it said, and a device intercepted at Spain’s Torrejon de Ardoz air force base in the early hours of Thursday morning.
A fifth device was received at Spain’s Defence Ministry on Thursday morning and defused by specialist police officers, a defence ministry spokesperson told Reuters.
A source close to the investigation told Reuters that the devices sent to the prime minister’s office, the Ukrainian embassy, the air base and the arms manufacturer were in similar brown envelopes and addressed to the heads of each institution.
They contained loose gunpowder with an electrical ignition mechanism that would make the powder burn, rather than explode, the source said.
Spain’s Correos postal service has been asked to collaborate in a pre-screening of all similar envelopes, the source added.
Spain’s High Court that specialises in terrorism has opened an investigation, a judicial source said.