A video of a Tube driver leading passengers in chants of "free Palestine" was "disturbing", the Transport Secretary said on Monday.
Mark Harper welcomed an investigation by TfL and the British Transport Police after the clip was widely shared online.
It appeared to show the driver leading demonstrators over the train tannoy as they travelled on the Central Line towards a mass protests at Marble Arch on Saturday.
TfL has claimed it does not know which employee was responsible, but says it has launched an investigation.
Mr Harper told Sky News: "I saw that clip and on the face of it it was disturbing, but I know the British Transport Police and Transport for London are investigating that.
"Because they are investigating that it wouldn't be right for me to comment on an ongoing police investigation, but they took that very seriously and I thank them at the weekend for their vigilance on that matter.
"I want to make sure people across the country are secure and those sorts of things will have been very concerning, particularly to people in the Jewish community."
The driver appeared to say "free, free" to which the passengers responded "Palestine".
He added: "Hope you all have a blessed day. Look after yourselves. Keep all those people in your prayers."
The pro-Palestine protest saw some demonstrators chant "jihad".
British Transport Police Assistant Chief Constable Sean O’Callaghan said the force was "aware of footage circulating on social media which suggests chants are led by driver of a train in London earlier".
"BTP are working with Transport for London and investigating the matter."
