US Representative Ileana Ros-Lehtinen, chairperson of the US House of Representatives Committee on Foreign Affairs, has issued a stern warning to US Vice President Joe Biden not to discuss arms sales to Taiwan while he is in China this week.

The warning came in a letter that was hand-delivered to Biden just before he boarded a plane to Beijing from Washington on Tuesday.

It followed a firm promise issued earlier in the week by the White House that arms sales would not be discussed and reflected suspicion in Congress that the administration of US President Barack Obama is being unduly influenced by Chinese sentiment on the arms sale question.