NEW DELHI (Reuters) - India is “disappointed” by China’s decision to again block its request at the United Nations to blacklist the head of a Pakistan-based militant group, the country’s foreign ministry said in a statement on Thursday.

India, backed by the United States, has been trying to get Maulana Masood Azhar on a U.N. list of groups with ties to Al Qaeda, blaming his group for a series of attacks in India, including one on its parliament in 2002 and another last year on an airbase.

But China, a member of the U.N. Security Council, has repeatedly put a technical hold on the Indian request citing a lack of consensus, a claim India rejects.

“We are deeply disappointed that once again, a single country has blocked international consensus on the designation of an acknowledged terrorist and leader of U.N.-designated terrorist organization, Masood Azhar,” India’s foreign ministry said.

China’s foreign ministry spokeswoman Hua Chunying said last month there were clear rules for listing a person or group as a terrorist, and that China has always believed the relevant U.N. committee should operate on the principles of objectivity.

The wrangling over Masood Azhar, a longtime Indian foe, has become a thorny issue in ties between China and India.

India worries that China will stick by its “all-weather” friend, India’s arch-foe Pakistan.

“India strongly believes that double standards and selective approaches will only undermine the international community’s resolve to combat terrorism,” India’s foreign ministry said.