An apparent bomb concealed inside an envelope exploded at the Ukrainian Embassy in Madrid, Spain, on Wednesday, injuring a worker handling the letter, according to reports and Spanish and Ukrainian officials.Kuleba also called on Spanish authorities to "urgently" investigate what Ukrainian officials described as an "attack."Ukraine's foreign affairs ministry spokesperson Oleg Nikolenko said in a tweet: "An explosive device hidden in an envelop [sic] detonated inside the embassy of Ukraine in Madrid."During a check, the envelope exploded in the hands of the embassy's manager," Nikolenko told the news outlet, adding, "The manager received light injuries, he was hospitalized and is receiving the necessary medical assistance.Meanwhile, Nikolenko said, "Whoever stands behind staging this explosion, they won't succeed in scaring Ukrainian diplomats or halting their daily efforts to strengthen Ukraine and counter the Russian aggression," according to the AP."