"We have to vet our refugees," Mr. Farage said, accusing the German Chancellor of allowing too many people into the country without proper checks in place.
Earlier, Mr. Farage turned to Twitter to square the blame with Angela Merkel:
Terrible news from Berlin but no surprise. Events like these will be the Merkel legacy.— Nigel Farage (@Nigel_Farage) December 20, 2016
But then Mr. Farage faced criticism from Brendan Cox, whose wife MP Jo Cox was murdered in June 2016.
Mr. Cox tweeted: "@Nigel_Farage blaming politicians for the actions of extremists? That's a slippery slope Nigel."
@Nigel_Farage blaming politicians for the actions of extremists? That's a slippery slope Nigel— Brendan Cox (@MrBrendanCox) December 20, 2016
Responding to the tweets from Mr. Cox on live radio, Nigel Farage said: "I'm sorry Mr. Cox but it is about time people started to take responsibility for what has happened.
"Mrs. Merkel has directly caused a whole number of social and terror problems in Germany. It's time we confronted that truth."
Mr. Farage also criticized Brendan Cox for supporting counterextremism group, Hope Not Hate.
We now live in a world where Nigel Farage mocks Brendan Cox in his grief, and none of Farage's supporters will think this is wrong.
— Ralf Little (@RalfLittle) December 20, 2016
Angela Merkel is facing an election in 2017 amid criticisms over her policy to open Germany's doors to half a million Syrian refugees, as well as subsequent gains by far-right populist parties in many parts of the country.
Commenting on the Berlin attack, Chancellor Merkel said the country is "united in sorrow" and the perpetrator "will be punished as harshly as the law allows."