Eight wars between states were fought in 2025. The year before, there were four. Researchers at the Uppsala Conflict Data Program (UCDP) at Uppsala University in Sweden say that is the most since they began collecting data in 1946, and the highest level since World War II.
“We are seeing a clear increase in conflicts between states,” said Shawn Davies, a senior analyst at UCDP. “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 eight are Russia and Ukraine, Iran and Israel, India and Pakistan, Thailand and Cambodia, Israel’s conflicts in Syria and in Yemen, the border conflict between Afghanistan and Pakistan, and the fighting in the Red Sea and Gulf of Aden between the U.S. and U.K. on one side and Yemen’s Houthis on the other.
The death toll
UCDP counted 65 active conflicts in 2025. The other 57 were fights inside countries, with government forces against rebel groups. Thirteen reached the level of war, meaning more than 1,000 battlefield deaths in a year.
About 244,600 people were killed in conflict, up from 187,000 in 2024. Therése Pettersson, a senior analyst and project manager at UCDP, said it was “not only a story of more conflicts, but also of extremely high levels of lethal violence.” Most striking, she said, was a dramatic rise in violence aimed at civilians, particularly in Sudan.
The Russia-Ukraine war was the deadliest interstate conflict, accounting for 62% of all battle-related deaths. The researchers put Russian dead at 77,700 and Ukrainian dead at 14,000 for the year. Neither side regularly releases casualty figures, so Uppsala works from open sources, including social media. Russian losses have grown while Ukraine’s stayed fairly stable, the team noted.
The Israel-Hamas war ranked second with 14,400 deaths, fewer than the year before because of ceasefire agreements. Sudan was third with 12,200, and that counts only fighting between government forces and the paramilitary Rapid Support Forces. Sudan dominates the record on violence against civilians. Tens of thousands of Sudanese civilians were killed by the RSF in massacres after the capture of El Fasher alone.
Why now
The researchers tie part of the decade-long rise to a shift in the international order the U.S. has led since World War II. “Now the United States is turning against the world order it built, as expressed in its 2025 National Security Strategy,” the study said, adding that the record number of interstate conflicts lends credence to voices arguing that “we are witnessing the end of Pax Americana and the liberal world order.”
Asked whether wars had worsened under the Trump administration, co-author Pettersson said the data cannot establish a direct causal link between specific U.S. policy changes and the 2025 increase. The trend, she said, predates the current administration and cannot be explained by any single policy decision or leader.
Nor do the researchers expect relief. Figures for 2026 so far suggest the rise in conflicts is likely to continue.
