US Defense Secretary Leon Panetta warned Thursday against unilateral U.S. military intervention in Syria, stressing that making a decision in this regard would be "a grave mistake".

US Defense Secretary Leon Panetta warned Thursday against unilateral U.S. military intervention in Syria, stressing that making a decision in this regard would be "a grave mistake".

Panetta made his remarks while commenting on the speech delivered by Emir of Qatar Hamad Bin Khalifa Al-Thani at the United Nations General Assembly Wednesday.

“The call of Emir of Qatar for military intervention in Syria will not change my conviction that such an intervention would be "a serious mistake,” Panetta told reporters at the Pentagon.

“The best approach is the international diplomatic and economic pressure on (the Syria President) Bashar al-Assad to step down,” he said.

The US Defense Secretary stated that once the international community decides to take a military action if necessary “we (the US administration) will be a part of it.” However, a unilateral US military intervention in Syria would be a “grave mistake.”

Panetta noted that the US is working with other countries to help the Syrian opposition and to provide the for those affected by the violence in Syria with humanitarian assistance, stressing that US officials are watching closely the sites of chemical and biological weapons in the Arab country.