The number of armed conflicts worldwide reached its highest level since World War II last year, while conflict-related deaths climbed to their deadliest levels in more than three decades, according to a new study by researchers at Sweden's Uppsala University.

Researchers with the Uppsala Conflict Data Program, widely regarded as one of the world's leading trackers of armed violence, recorded 65 active conflicts last year, according to KPBS.

The study found that direct conflicts between states doubled from the previous year to eight, the highest number since the organization began collecting data in 1946.

The interstate conflicts identified by the researchers included the wars involving Russia and Ukraine, Iran and Israel, India and Pakistan, Thailand and Cambodia, as well as Israel's military operations in Syria and Yemen.

The list also included border fighting between Afghanistan and Pakistan and clashes in the Red Sea and Gulf of Aden involving U.S. and British forces against Yemen's Houthi rebels.

"We are seeing a clear increase in conflicts between states," said Shawn Davies, a senior analyst at Uppsala. "For a long time, interstate wars were relatively rare, but developments in recent years point to growing international tensions and a changing global security order."

The remaining 57 conflicts were classified as intrastate wars and insurgencies involving governments and armed groups operating within national borders.

The report estimated that approximately 244,600 people were killed in conflicts worldwide last year, up sharply from 187,000 deaths in 2024. The total marks the highest annual conflict death toll since 1994, the year of the Rwandan genocide.

"It is not only a story of more conflicts, but also of extremely high levels of lethal violence," said Therése Pettersson, senior analyst and project manager at UCDP. "Most notably, we see a dramatic increase in violence directed against civilians, particularly in Sudan."

Researchers categorize violence into three major groups: state-based violence involving governments, non-state violence between armed groups, and one-sided violence targeting civilians.

Of the 65 conflicts recorded last year, 13 met the threshold for full-scale war, defined as causing more than 1,000 battlefield deaths annually.

The war between Russia and Ukraine remained the deadliest interstate conflict, accounting for 62% of all battle-related fatalities worldwide. Researchers estimated that approximately 77,700 Russian troops and 14,000 Ukrainian troops were killed last year.

The war between Israel and Hamas ranked as the second-deadliest conflict, causing an estimated 14,400 deaths. While still among the world's bloodiest wars, fatalities declined compared with the previous year amid cease-fire agreements.

Sudan ranked as the third-deadliest state-based conflict with 12,200 deaths resulting from fighting between government forces and the paramilitary Rapid Support Forces.

Researchers said Sudan also experienced some of the worst violence against civilians, with tens of thousands reportedly killed in attacks and massacres attributed to the RSF, particularly following its capture of the city of El Fasher.

The study suggested that part of the increase in global conflict may be linked to broader shifts in the international system that has existed since World War II.

"The extremely high number of conflicts and wars recorded in 2025, particularly the record number of interstate conflicts, lends credence to the growing number of voices arguing that we are witnessing the end of Pax Americana and the liberal world order," the report said.

However, Pettersson cautioned against drawing direct connections between the increase in conflicts and any single government or administration.

"Our data does not allow us to establish a direct causal link between specific U.S. policy changes and the increase in conflicts recorded in 2025," she said.