Beijing (PTI): China's postal service has suspended mailing of parcels with sealed liquids and powder as part of ramped up security measures for the Beijing Olympics.

The new step from June 1 to October 31 was to tighten security ahead of and during the Games in August, a State Post Bureau spokesman said.

Chemical products, powder goods, unidentified metal and mechanical and electrical products, sealed containers with unidentified gas or liquid are also banned from delivery, state-run Xinhua news agency said.

A safety certificate from local public security authorities is required to be produced by those having the necessity to mail parcels with the listed items, it said.

Beijing Postal bureau said last month that it would step up inspections of parcels being sent to Olympics host cities, including Shenyang, Tianjin, Qingdao, Shanghai and Qinhuangdao.

Chinese aviation authority also recently imposed a ban on carrying liquid in baggage on domestic flights. Security for the Olympics has been given top priority with authorities identifying terrorism as the "biggest threat" to the Games.

The head of Interpol Ronald Noble warned in Beijing recently that an attempted act of terrorism was a "real possibility" and China must be prepared for a possible strike by Al Qaeda or some other terrorist group during the Olympics.

Land, Navy and air forces would "participate in safeguarding the Games", a top official of the China's People's Liberation Army Command Team for Beijing Olympic Security Work said earlier.

China has claimed to have foiled plots to crash a Beijing-bound passenger aircraft and carry out bomb attacks on hotels and government offices in the Chinese capital during Olympics.