Washington would work with countries in the region to stop any attempt by Iran to "influence governments or political parties,” said US assistant Secretary of State Richard Boucher on Tuesday.

On the prospect of Iran, which is an observer in Shanghai Cooperation Organization (SCO) at present, becoming a member, Boucher said there were recent reports that Iran had already asked for membership.

He expressed concern over Iran’s potential membership with the six-nation SCO which comprises Russia, Uzbekistan, Kyrgyzstan, Kazakhstan, Tajikistan and China.

On the possibility of the organization welcoming Iran with open arms with the aim of strengthening regional cooperation, Boucher said "It depends on what form that cooperation takes."

He said, however, that Washington would not remain silent if there were signs the grouping was evolving in the direction of forming a military cooperation.