WASHINGTON - A clear majority of Americans see China as an economic threat, a poll showed Monday, as Barack Obama sought to bolster relations on his first trip to Beijing and Shanghai as president.

More than 70 percent of those questioned in the CNN poll said they considered the Asian giant to be an economic threat, while only 28 percent disagreed with the notion.

Two-thirds of those surveyed said they saw China as a source of unfair competition for American companies, while only a quarter viewed China positively as a huge potential market for US goods.

"That may be why 71 percent of Americans consider China an economic threat to the US," said CNN polling director Keating Holland. "Americans tend to view foreign countries as competition, and China is no exception."

Trade tensions between the powers have intensified in recent months, with both sides taking action against the other's imports.

Obama ignited the first major trade spat of his presidency when he imposed punitive duties on Chinese-made tires in September.

An angry Beijing lodged a complaint at the World Trade Organization and retaliated by launching a probe into possible unfair trade practices involving imports of US car products and chicken meat.

The CNN poll Monday showed that Americans were split on whether China posed a military threat with slightly more, 51 percent, agreeing with the statement than disagreeing (47 percent).

A quarter of the 1,014 people questioned in the weekend poll said China had a good track record on human rights, but 68 percent suggested the rights of Chinese citizens were not being respected.

Obama, in booming Shanghai Monday, pushed for an unshackled Internet and expanded political freedoms during a webcast town hall event.

On Chinese state television's evening news, Obama's visit was not even mentioned until 25 minutes into the broadcast. The main dispatch on the state news agency Xinhua on the Shanghai event did not include Obama's comments on Internet freedoms.