Two people were sent to hospital after a package containing a suspicious liquid was sent to Labour MP Mohammad Yasin's office.
Police were immediately called and staff members on the first floor of the Norman Shaw North building in Westminster were told to either stay shut in their offices or to leave the premises.
“Specialist officers attended and the package was assessed," a spokesman for the Metropolitan Police was quoted as saying by the media. "The substance contained in it was deemed not to be hazardous to health. The incident, which was contained to one room, has been stood down.”
The package, according to officers, were suspected to be linked to letters sent to Muslims in in some parts of the country calling for April 3 to be Punish a Muslim Day. The letters promised that people carrying out hate crimes against Muslims would be awarded points; 10 points for verbal abuse, 100 for beating and 2,500 to “nuke Mecca”.
“They have caused you pain and heartache. What are you going to do about it?” the letters supposedly said.
Recently, London Mayor Sadiq Khan opened up about racial abuse and death threats he received. At the South by Southwest Interactive Conference in Texas, Khan read out abusive tweets that called him a Muslim terrorist and a "gay muzzie" terrorist.
“I say kill the mayor of London and you will be rid of one Muslim terrorist,” one said. Another read: “@sadiqkhan is just a gay muzzie terrorist”.
“I could go on and on, but I won’t,” said Khan after reading out the abuses. “I don’t read these out to be portrayed as a victim, or to ask for sympathy. But ask yourself this – what happens when young boys and girls from minority backgrounds see this kind of thing on their timelines – or experience it themselves?
“Or someone thinking about becoming a politician? And what about young girls and women who are being driven from these platforms – reversing our long fight for gender equality?” questioned Khan.
Damian Talbot