KUALA LUMPUR, Malaysia — Sultan Muhammad V became the first monarch to abdicate in Malaysian history, cutting short his five-year term in an unexpected move after just two years on the throne.

The palace said in a statement on Sunday that the 49-year-old ruler had resigned as Malaysia’s 15th king with immediate effect, but it provided no explanation for why he was stepping down.

Muhammad V, the ruler of the northeast Kelantan State, took his oath of office in December 2016, becoming one of Malaysia’s youngest constitutional monarchs. He reportedly married a 25-year-old former Russian beauty queen in November while on a two-month medical leave.

News outlets in Russia and Britain and posts on social media showed pictures of the wedding, which reportedly took place in Moscow. Neither the sultan, the palace nor the government officially confirmed the wedding.