The Centre-State tension over central investigating agencies continues to simmer.

Chief Minister Pinarayi Vijayan said the Chief Secretary Viswas Mehta had shot off a letter to the Union Finance Secretary saying that a customs official probing the gold smuggling case had threatened a Kerala government official during interrogation.

"The name of the Customs official has also been passed on," the chief minister said in the Assembly on Wednesday. "Since such actions demoralise state government officials, the chief secretary has told the Centre that a probe should be initiated into the incident and exemplary action taken."

The chief minister, responding to a Calling Attention motion moved by CPM MLA V Joy, said that assistant protocol officer Harikrisnan, had written a complaint to the Chief Secretary on January 7, two days after he was subjected to interrogation by the Customs in Kochi.

The assistant protocol officer was summoned as part of the probe into the smuggling of goods using the diplomatic route. It is the Protocol Office that intimates the airport authorities whether diplomatic immunity should be given to any government-related consignment.

The chief minister said Harikrisnhan had, in his letter to the chief secretary, said that a Customs official had insisted that he give his statement in a certain way. "He was threatened with dire consequences if he did not do so," the chief minister said.

Joy, while moving the Calling Attention, said that the Customs official had even threatened serious consequences for even Harikrisnhan's mother if he did not give a statement as preferred by the Customs official.

Earlier, the State Government had alleged that the central investigating agencies, by interfering in the state's flagship programmes like Life Mission and K-FON, was attempting to sabotage Kerala's development and demoralise honest officials.