By Rafiq Sherzad
JALALABAD, Afghanistan (Reuters) - An American and an Afghan soldier were killed on Wednesday when a firefight broke out between Afghan and NATO coalition forces at a compound where a senior U.S. diplomat met a provincial governor in eastern Afghanistan, police and U.S. sources said.
Soldiers from both sides were wounded in the shooting, which erupted shortly after the diplomat left the compound aboard a helicopter, according to U.S. and Afghan sources.
A U.S. official, speaking on condition of anonymity, estimated that around six American personnel were wounded, but the Pentagon said only that "several" were injured in the attack.
"I can confirm that one American soldier was killed today," Colonel Steve Warren, a Pentagon spokesman, told reporters.
Asked whether this was an insider attack by an Afghan soldier turning his weapon against NATO forces, Warren said: "It's a little early to tell. Indications are leaning that way."
"But we need to let a little more information come out first," Warren added.
Two Afghan soldiers were also injured in the shootout, but it was unclear who had fired first, police said, adding that an Afghan soldier was being questioned.
The U.S. Embassy in Kabul issued a statement on the incident without referring to casualties.
"We are aware that there was an exchange of gunfire involving Resolute Support service members ... All Chief of Mission personnel of the visiting party are accounted for," the U.S. Embassy said.
The frequency of "insider attacks" in Afghanistan has fallen sharply this year as most foreign forces withdrew from the country in 2014.
A small contingent of around 12,000 NATO troops remains in Afghanistan to train Afghan forces after the combat mission officially ended last year.
Wednesday's incident was the first since January, when three U.S. military contractors were killed by an Afghan soldier in the capital Kabul.
In the final years of the war, dozens of incidents seriously eroded trust between Afghan forces and their international allies, forcing the coalition to scale back interaction with government troops.
The Taliban have sometimes claimed that insider attacks reflect their ability to infiltrate the enemy, but Afghan and coalition forces say incidents more often arise over misunderstandings or arguments between troops.
(Reporting Rafiq Sherzad in Jalalabad, Mirwais Harooni and Jessica Donati in Kabul, Phil Stewart in Washington, writing by Jessica Donati; editing by Simon Cameron-Moore and G Crosse)