WASHINGTON — Foreign arms sales by the United States jumped by almost $10 billion in 2014, about 35 percent, even as the global weapons market remained flat and competition among suppliers increased, a new congressional study has found.

American weapons receipts rose to $36.2 billion in 2014 from $26.7 billion the year before, bolstered by multibillion-dollar agreements with Qatar, Saudi Arabia and South Korea. Those deals and others ensured that the United States remained the single largest provider of arms around the world last year, controlling just over 50 percent of the market.

Russia followed the United States as the top weapons supplier, completing $10.2 billion in sales, compared with $10.3 billion in 2013. Sweden was third, with roughly $5.5 billion in sales, followed by France with $4.4 billion and China with $2.2 billion.

South Korea, a key American ally, was the world’s top weapons buyer in 2014, completing $7.8 billion in contracts. It has faced continued tensions with neighboring North Korea in recent years over the North’s nuclear weapons program and other provocations. The bulk of South Korea’s purchases, worth more than $7 billion, were made with the United States and included transport helicopters and related support, as well as advanced unmanned aerial surveillance vehicles.