Pakistan on Thursday rejected as "false" and "baseless" Indian Prime Minister Narendra Modi's claims of having launched a surgical strike on terrorist camps in Pakistani territory.

At an interactive session at the Central Hall Westminster in London, Modi said on Wednesday that Islamabad was informed about the 2016 surgical strike before this was made known to the media.

Pakistan's Foreign Office spokesperson Mohammad Faisal told the media that the claims about the surgical strike by the Indian military was a "lie" and "repeating it doesn't turn it into the truth".

India said its special forces conducted the surgical strike across the Line of Control (LoC), which divides Jammu and Kashmir between the two countries, on September 29 and inflicted heavy casualties on terrorists preparing to infiltrate into Indian Kashmir.

In a veiled message to Pakistan, Modi said in London that "antics of those exporting terror and trying to backstab us will not be tolerated" and "they will be answered in a language they understand".

Spokesperson Faisal said: "Repeating a lie doesn't turn it into the truth... It is the other way around and India is backing terrorists in Pakistan.

"The whole world knows who the terrorists are and who their head is. Indian spy Kulbhushan Jadhav is a proof of Indian state-sponsored terrorism," he said.