"Returning to the US, I think, is the best resolution for the government, the public, and myself, but it's unfortunately not possible in the face of current whistleblower protection laws, which, through a failure in law, did not cover national security contractors like myself," Xinhua quoted Snowden as saying on the website of advocacy group "Free Snowden".
"This is especially frustrating, because it means there's no chance to have a fair trial, and no way I can come home and make my case to a jury," Snowden added.
This is Snowden's second public online Q&A session since the first one hosted by the Guardian last June after he first revealed the US National Security Agency's secret intelligence surveillance programmes.
The 30-year-old former NSA contractor is currently living in Russia under temporary asylum and facing espionage charge for his leaks about the NSA surveillance practices in his home country.
Snowden, who regarded himself as a whistleblower of wrongdoing, also explained that current US whistleblower protection laws in the US "do not protect contractors in the national security arena".
"If we had had a real process in place, and reports of wrongdoing could be taken to real, independent arbiters rather than captured officials, I might not have had to sacrifice so much to do what at this point even the president seems to agree needed to be done," he said.
Snowden's latest public comments come after US President Barack Obama offered his proposals to change the NSA controversial surveillance practices last week in a highly anticipated and carefully worded speech.
In the speech, Obama outlined his plan to pull back part of the bulk collection of US citizens' phone records while again highlighted his defence for the overall intelligence surveillance practices.