Muslim MPs have been sent threatening letters which urge people to carry out acid attacks against Muslims, bomb mosques and pull off hijabs.
Khan's package was unopened by his staff but the package to Huq was opened and a member of staff was taken to hospital as a precaution after opening the letter, which the MP said contained a "sticky substance" that the police had described as "low-level noxious".
Officers are thought to have been concerned that the Islamophobic "malicious communication" was linked to letters sent to Muslims in London, Yorkshire and the Midlands in recent days calling for April 3 to be Punish a Muslim Day.
An urgent question was raised in the House of Commons by Labour MP Yasmin Qureshi after reports that letters were sent out in a number of United Kingdom cities, calling on people to verbally and physically attack Muslims.
It emerged today that two more suspicious packages have been sent to the Houses of Parliament, with another man taken to hospital.
Huq said she had been assured that the substance was not harmful, but told the BBC that the parcels were now "part of a pattern".
Yasin won his Bedford seat from the Conservatives by 789 votes at the last general election.
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"The affected areas were temporarily cordoned off but no evacuation was necessary", a spokesman said.
Labour MP for Walthamstow, Stella Creasy, said she found out that some of her constituents had received the letters on Friday evening while helping others report anti-Semitic graffiti.
It released a statement, saying: "It is essential that all letters and envelopes are kept and handled minimally to preserve evidence for the police to investigate".
Labour's Yasmin Qureshi asked an urgent question in parliament on Monday on the racist letters. "One person attended hospital as a precaution".
Scotland Yard confirmed that specialist officers had been sent to the scene to assess the packages, which were deemed non-hazardous.
"Sadly, it is reflective of hate against Muslims which continues to manifest itself alongside the rise of the far-right", said the council, which represents some 2.7 million British Muslims.
"As chair of the race all-party parliamentary group I stand in solidarity with them and their hard-working staff".