Last month in Sri Lanka, a powerful Buddhist monk went on a hunger strike that resulted in the resignation of all nine Muslim ministers in the cabinet. The monk had suggested that Muslim politicians were complicit in the Easter Sunday attacks by Islamic State-linked militants on churches and hotels in Sri Lanka, which killed more than 250 people.

In Myanmar, where a campaign of ethnic cleansing has forced an exodus of most of the country’s Muslims, Buddhist monks still warn of an Islamic invasion, even though less than 5 percent of the national population is Muslim. During Ramadan celebrations in May, Buddhist mobs besieged Islamic prayer halls, causing Muslim worshipers to flee.

Because of Buddhism’s pacifist image — swirls of calming incense and beatific smiles — the faith is not often associated with sectarian aggression. Yet no religion holds a monopoly on peace. Buddhists go to war, too.

“Buddhist monks will say that they would never condone violence,” said Mikael Gravers, an anthropologist at Aarhus University in Denmark who has studied the intersection of Buddhism and nationalism. “But at the same time, they will also say that Buddhism or Buddhist states have to be defended by any means.”

Given that Theravada Buddhists constitute overwhelming majorities in the five countries where their faith is practiced — Sri Lanka, Myanmar, Cambodia, Laos and Thailand — it might seem strange that they feel so besieged. But Buddhism, whose adherents make up only 7 percent of the global faithful, is the only major religion whose population is not expected to grow in absolute numbers over the next few decades, according to the Pew Research Center.

Meanwhile, the number of Muslims, who make up just under one-quarter of the world’s population, is growing quickly, buoyed by youthful demographics and high fertility rates. By 2050, Pew projects that there will be nearly as many Muslims in the world as there are Christians.