A day after he was detained and questioned at Heathrow Airport by custom officials for over eight hours, Yoga Guru Baba Ramdev claimed that the customs officials seized documents from him that carried corruption proof against the Congress, reported CNN-IBN.

"They took two diaries. Both were on corruption done by the UPA government," Ramdev said.

Ramdev said he was not given any explanation for the action by the authorities and claimed he was not involved in anything illegal.

"I have never done anything wrong or illegal in my life. I was detained for eight hours at the airport, but was not given any explanation. I asked them repeatedly to give me a reason for detention; but they told that they cannot disclose it to me," Ramdev said.

Ramdev's detention has drawn criticism from the BJP which urged the Centre to intervene. BJP President Rajnath Singh termed the detention of the yoga guru as "serious" issue and asked the Centre to take cognisance of the matter.

"The reasons for his detention have not been made public...as I know, he was detained at the airport for

carrying a diary carrying mantras. The diary has been seized and he has been called for fresh questioning today also," Singh told reporters in New Delhi.

There was lack of clarity over the reason for his detention at the airport.

Ramdev went to London to attend the function organised by the Patanjali Yogpeeth on the 120th anniversary of Swami Vivekananda in the next couple of days.

According to one of the organisers of the function, Ramdev was questioned on books he was carrying which were in Hindi and Sanskrit. The officials detained Ramdev for over six hours before he was allowed to go.

However, a source said, Ramdev was questioned by customs officials as he came here on a visitor visa instead of a business visa.

Some media reports also said that Ramdev was questioned about certain medicines he was carrying with him.

Ramdev's spokesman SK Tejarawala described as "baseless" that he was being questioned on carrying some medicines.

With inputs from PTI