The accession of India and Pakistan as full members of the Beijing-backed Shanghai Cooperation Organisation, despite lingering concerns over regional rivalry between China and India, will be formally announced during its annual summit on June 8 and 9 in Astana, Kazakhstan, which will be attended by Chinese President Xi Jinping.

According to Chinese media, the inclusion of the two countries, which previously held observer status, will “add to the potential and the global influence of the Shanghai Cooperation Organisation,” China’s assistant foreign minister, Li Huilai, said.

The SCO, seen by some as a counterweight to the US-and European-led North Atlantic Treaty Organisation (Nato), is a political and security organisation that facilitates counter-terrorism cooperation. Its members are China, Russia, Kazakhstan, Uzbekistan, Tajikistan and Kyrgyzstan.

The inclusion of India and Pakistan is expected to test the group’s internal cohesion. China will assume the rotating chairmanship of the group next year, and will now face the challenge of managing bitter relations between Pakistan and India, as well as its own rivalry with New Delhi.

“I want to stress that China and India are important neighbours,” Li told reporters on Monday, “Developing China-India relations does not only fit the interests of the two countries, but also the interests of the region and the world.”

The two Asian giants have long viewed each other with suspicion. China’s opposition to India joining another security organisation, the Nuclear Suppliers Group, has further strained bilateral ties. Li said the question of India’s bid to join the NSG is “more complicated than imagined” but added that China would support an eventual solution through consultations among the group’s members.

New Delhi is sceptical of China’s infrastructure projects in Pakistan and Sri Lanka, fearing they might be used for military purposes and as an attempt to encircle India. New Delhi skipped a summit in Beijing last month on China’s “Belt and Road Initiative”, an ambitious plan to promote global trade.

This year’s SCO meeting would also explore the possibility of Iran joining the group, a move that China would welcome, Li said. Iran is an observer state at the group. “China welcomes and supports Iran’s wish to become a formal member of the SCO,” Li said.

According to China Daily, the inclusion of Pakistan and India in the SCO will make it one of the biggest regional organisations, covering about half of the world’s population.

Analysts said that while the increase in members may bring a bigger variety of voices in the organisation, any disagreements can be resolved through communication and consultation.

The two new countries will go through official procedures to become members during the 17th meeting of the Council of Heads of State of the SCO, Assistant Foreign Minister Li Huilai said.

Xi will make a state visit to Kazakhstan at the invitation of Kazakh President Nursultan Nazarbayev from Wednesday to Saturday. He will attend the SCO summit and the opening ceremony of Astana Expo 2017.

By accepting the two countries, the SCO will expand its geographical coverage to South Asia. It will account for three-fifths of the area of Eurasia, he added.

The SCO launched accession procedures for India and Pakistan in July 2015 at the Ufa summit in Russia. At the SCO’s Tashkent summit in Uzbekistan in June 2016, SCO members signed the memorandum on the obligations for India and Pakistan to obtain membership in the SCO.

During Xi’s visit, China and Kazakhstan will sign cooperation documents in such areas as production capacity, investment, finance and trade, Li said. The two presidents will speak on a video conference call on Eurasia cross-border transportation, talking to people such as port workers in East China, he added.

Kazakhstan has played a leading role in jointly building the Belt and Road, and with China has agreed on 51 projects of production capacity, with a total investment of $27 billion, Li said.

Xing Guangcheng, a senior researcher of Russian and Central Asian studies at the Chinese Academy of Social Sciences, said that the incoming members of the SCO will bring more energy to the organisation and increase its influence.

“Any expansion in an organisation can be a double-edged sword,” he said, adding that SCO members may have different interpretations of the organization and different voices may emerge in the future.

Wu Hongwei, another Central Asian studies researcher at CASS, said SCO members can cultivate cooperative potential in economics, culture and education, and reach consensus through more dialogue.