Liberal Democrat lawmaker Chris Rennard tweeted that there was a "cyber security attack on Westminster; Parliamentary e-mails may not work remotely."
A House of Commons spokesman confirmed that "the Houses of Parliament have discovered unauthorised attempts to access parliamentary user accounts.
"We have systems in place to protect member and staff accounts and are taking the necessary steps to protect our systems," it added.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
Get the latest election news, live updates and election schedule for Lok Sabha Elections 2019 on ndtv.com/elections. Like us on Facebook or follow us on Twitter and Instagram for updates from each of the 543 parliamentary seats for the 2019 Indian general elections.