On a cold October night, a small team of Afghan intelligence commandos and American Special Operations forces carried out a raid on a village where they believed a leader of Al Qaeda was hiding. That night the Afghans and Americans got their man, Abu Bara al-Kuwaiti. They also got what officials from both countries say was an even bigger prize: a laptop computer and files giving details of Al Qaeda operations on both sides of the border. American military officials said the intelligence seized in the raid was possibly as important as the information found on the computer and documents of Osama bin Laden in Abbottabad, Pakistan after members of the Navy SEALs killed him in 2011.

The increase in raids is not in line with policy declarations in Washington, where the Obama administration has deemed the American role in the war essentially over. But the increase reflects the reality in Afghanistan, where fierce fighting in the past year killed record numbers of Afghan soldiers, police officers and civilians. American and Afghan officials said that American forces were playing direct combat roles in many of the raids and were not simply going along as advisers. The raids appear to have targeted a broad cross section of Islamist militants. They have hit both Qaeda and Taliban operatives, going beyond the narrow counterterrorism mission.

American and Afghan officials said the intelligence obtained from the October mission was not the sole factor behind the surge in raids. Around the same time that Afghan and American intelligence analysts were poring over the seized laptop and files, Afghanistan’s newly elected president, Ashraf Ghani, signed a security agreement with the United States and eased restrictions on night raids by American and Afghan forces that had been put in place by his predecessor,  Hamid Karzai  who  had also sought to limit the use of American air power, even to support Afghan forces.

Mr. Karzai’s open antipathy to the United States helped push the Obama administration toward ordering a more rapid drawdown than American military commanders had wanted. And while the timetable for the withdrawal of most American troops by the end of 2016 remains in place, the improving relations under Mr. Ghani pushed the Obama administration to grant American commanders greater latitude in military operations, American and Afghan officials said.American commanders welcomed the new freedom. Afghan forces were overwhelmed fighting the Taliban in some parts of the country during last year’s fighting season, which typically runs from the spring into the autumn. Many Western officials fear that this year’s fighting season could be even worse for the Afghans without the air power and logistical support from the American-led coalition, and without joint Afghan-American night raids to keep up pressure on insurgent commanders.