Beijing said on Tuesday it was “seriously dissatisfied” by the visit of an Indian leader to a disputed Himalayan region, the latest tense exchange between the Asian giants over border areas claimed by both. China's foreign ministry spokesman Ma Zhaoxu accused an unnamed Indian leader of ignoring China's concerns by visiting the state of Arunachal Pradesh. Prime Minister Manmohan Singh travelled to the mountainous state, twice the size of Switzerland, earlier this month to woo voters ahead of Tuesday's state assembly election. Beijing lays claim to 90,000 sq km of land in the border state, that it sees as “southern” Tibet and had already expressed its anger about a planned visit by the Dalai Lama in November. “We demand the Indian side pay attention to the serious and just concerns of the Chinese side, and do not provoke incidents in the disputed region, in order to facilitate the healthy development of Sino-Indian relations,” Ma said in a statement posted on the Foreign Ministry . India's foreign ministry said its leaders were free to visit states where elections are held. “Well, regardless of what others say it is the Government of India's stated position that Arunachal Pradesh is an integral part of India,” Foreign Minister S.M. Krishna told reporters in New Delhi. The ministry said in a statement that New Delhi was “disappointed and concerned.”