The Taliban initially said that Newlove was captured alive. Zabiullah Mujahid, a spokesman for the Taliban, did not offer an explanation for how he died.
Mujahid did, however, tell The Associated Press news agency in Kabul that two days ago the Taliban left the "body of a dead American soldier for the US forces".
Both sailors were assigned to a training school for Afghan security forces, according to US military officials. But the school is headquartered in Kabul.
Nato officials have not explained why the two sailors were traveling in Logar, an increasingly dangerous province in eastern Afghanistan.
General Mustafa Mosseini, the chief of police of Logar province, said Nato troops removed Newlove's body on Wednesday. He said he believed that the body had been washed downstream after rains on Tuesday night.
Mosseini also noted that in recent days, the Taliban were being pressured by Nato forces in the area.
"The security was being tightened," he said. "Searches continued from both air and the ground. Militants were moving into Pakistan."