Organizers of Expo 2010 Shanghai are stepping up patrols and security checks after two men tried, but failed, to take their own lives in the Expo Garden.

In separate incidents on July 22 and 23, two men threatened to kill themselves by jumping off the Expo Culture Center and the South Korea Pavilion respectively. Police stopped both attempts.

Officials did not say what prompted the suicide attempts, but witnesses reportedly said both men were distraught, apparently upset by personal affairs and disputes.

"We do not encourage or allow activities unrelated to visiting (in the Expo garden)," Hong Hao, bureau chief of Shanghai World Expo Coordination, said at a press conference yesterday.

Organizers will enhance security to help prevent any further incidents, said Hong.

Measures include tighter checks at entrances, identifying possible suicide locations and increasing on-site patrols by security staff.

More than 34.8 million people have visited the Expo as of Saturday, most of them from the Chinese mainland.

At Saturday's press conference, Hong denied that schools and State-owned companies were forced to organize students and employees for visits to the Expo to boost record attendance figures. The Shanghai Expo must attract at least 70 million people to pass the mark.

Such assertions are baseless, Hong insisted.

"The 70 million we anticipate is an estimated number, not a target," he said.

In recent weeks, more than 400,000 visitors have passed through the Expo turnstiles daily, more than double the number each day when it first opened in May. The low attendance initially had organizers concerned, reports said.

The organizers have stressed their main priority is that visitors to the Expo enjoy the experience safely. No major accidents were reported so far.