US Ambassador to Pakistan Richard Olson has said that a military operation in North Waziristan is the internal matter of Pakistan, reported Radio Pakistan on Thursday.
In an interview to a private TV channel, Olson said that action would be taken against Maulvi Fazlullah if any credible evidence is found about his presence in Afghanistan.
Earlier, US special envoy for Afghanistan and Pakistan Marc Grossman had also said that America is not pushing Pakistan to launch a military operation in North Waziristan. The Pakistani government has maintained that an operation will not be carried out without reaching a consensus on the issue.
The US has long been calling on Pakistan to go after Afghan insurgents and the Haqqani network believed to be based in North Waziristan.
Islamabad had voiced concerns when US Defence Secretary Leon Panetta disclosed that the Pakistani military was planning to start an operation against militants in North Waziristan, which invited strong criticism in Pakistan.