Iran's government has prevented direct access to the social media sites since 2009, saying they were being used by anti-government protesters to organize rallies, The New York Times reported.
Savvy Internet users in Iran have used virtual private networks, or VPNs, to connect to blocked websites through computers located outside of the country, though even that method has been throttled by the government.
Technical glitches over the years have led to temporary direct access to the censored websites, and while some users believe that may be what happened Tuesday, others think it might be a sign such government censorship may be on its way out, the newspaper said.
New Iranian President Hassan Rouhani has repeatedly promised to reduce Internet censorship, though hard-liners have fought to retain the firewalls, the Times reported.
Sources told the newspaper the glitch could have been caused by infighting between groups with opposing opinions on censorship.