Serbia‘s parliament formally accepted the resignation of Prime Minister Milos Vucevic on Wednesday, triggering a 30-day deadline to form a new government or call early elections.

Reuters reported that Vucevic, head of the ruling Serbian Progressive Party (SNS) and an ally of President Aleksandar Vucic, resigned amid protests sparked by the collapse of a tent at a train station in the northern city of Novi Sad last November, in which 15 people died.

More than 100,000 protesters descended on Belgrade on Saturday in one of the largest rallies in decades. Protesters say the train disaster was a symptom of widespread corruption and mismanagement, which the government denies.

Under the constitution, President Vucic now has 30 days to propose a new prime ministerial candidate to lead the government until 2027, when parliamentary and presidential elections are scheduled.

“The Serbian parliament, … acknowledged the resignation of the prime minister and the government’s term of office ends,” parliament speaker Ana Brnabic said. “The deadline for … the new government expires at midnight on April 18.“