"We are testing a new civic engagement feature that shows people on Facebook the top posts from their elected officials," a Facebook spokesperson said.
To reach this conclusion, the researchers set up an online test that used a bank of 40 images created from 10 original images sourced from Google Images.
Congress spokesperson Randeep Singh Surjewala in a series of tweets said some news channels were running "fake news" on Gandhi's alleged meeting with Chinese Ambassador Luo Zhaohui.
Facebook has been working to improve people's experience in News Feed by showing more stories that it thinks they will find informative and entertaining.
Google also has reprogrammed a popular feature to omit derogatory suggestions from its automated recommendations of search requests.
The security improvement was described as being part of a broader effort to rid the leading social network of hoaxes, misinformation, and fake news by making sure people are who they claim to be.
The new feature uses non-partisan third-party organisations like Snopes and Politifact to assess the factual accuracy of stories reported as fake by users.
"I own nothing in Russia, I have no loans in Russia, I don't have any deals in Russia," Trump said. "Russia is fake news".
The Facebook founder, Mark Zuckerberg said that fake news, polarised views and "filter bubbles" were damaging "common understanding".
The social media giant says it will now look at the number of publishers posting about the same topic "not just the number of people sharing.
The move comes as social media giants face increasing scrutiny over their role in the explosion of so-called "fake news" - which is believed to have influenced the US election - as well as online bullying and hate speech.
"The company uses surveys somewhat like this to test the general quality of the news feed, and it has used other metrics to attempt to define rules for finding clickbait and fake stories. This appears to be the first direct coupling of those two practices: old parts doing a new job,"