A letter bomb delivered to the Ukrainian Embassy in Madrid explodes.

MADRID — A letter bomb delivered to the Ukrainian Embassy in Madrid exploded on Wednesday, mildly injuring an employee who was inspecting it, Ukrainian and Spanish officials said.

Ukraine’s foreign minister, Dmytro Kuleba, ordered all Kyiv’s embassies to strengthen security after the attack.

The embassy’s manager was checking an envelope received in the mail when it exploded in his hands, Oleh Nikolenko, a spokesman for Ukraine’s Foreign Ministry, said in a statement on Telegram.

The Spanish National Police said they were investigating the episode and that no suspects had been identified. The employee, who sustained a minor injury to a finger on his right hand, was treated at a hospital and has been released.

The envelope, which arrived with the embassy’s regular mail delivery, was addressed to Serhii Pohoreltsev, Ukraine’s ambassador to Spain, a spokesman for Madrid’s government said in a statement.

The embassy could not be reached for comment.

The police said they were contacted at about 1:20 p.m. by the embassy, which is in the eastern part of the Spanish capital. The police sent a bomb squad and a canine unit to the site and the area was cordoned off.