Indian protesters hold a scratched photo of Jaish-e-Mohammed group chief, Masood Azhar, as they shout slogans against Pakistan during a protest in Mumbai on Feb. 15, 2019.

A series of retaliatory air strikes between India and Pakistan last month escalated already tense relations between the two South Asian nuclear powers. A UN vote set for Wednesday could further increase tensions — and China may be the key.

After Pakistan-based militant group Jaish-e-Mohammed claimed responsibility for February's suicide attack that killed 40 Indian security officers in Kashmir, three members of the United Nations Security Council moved a proposal to sanction JeM leader Masood Azhar as a global terrorist.

If passed, the proposal from France, the United Kingdom and the United States would subject Azhar to an assets freeze, travel ban and arms embargo.

On Wednesday, the Security Council is set to vote on whether to designate Azhar as a global terrorist. While JeM has been listed by the UN as a terror group since 2001, efforts to blacklist its leader have not been successful — February's proposal marks the fourth attempt in 10 years.

China, a permanent veto-wielding member of the Security Council and Pakistan's "all-weather" ally, blocked previous attempts in 2009, 2016 and 2017, claiming in the second instance that the militant leader did not meet "the Council's requirements" to be a terrorist.

Although Pakistan has clamped down on other militant groups such as the local Taliban, JeM continues to operate publicly in the country. Azhar openly runs camps in several towns across Pakistan — including a camp in Balakot, which India said its Air Force hit during a strike on Feb. 25.

Indian politicians and experts have suggested that Islamabad supports the group because it helps Pakistani political aims. The country "pursues its strategic goals by sponsoring, training, equipping, and financing terror groups that attack targets in India, Afghanistan, and Iran," Indian Member of Parliament Shashi Tharoor wrote in a recent commentary.

As Wednesday's vote draws closer, all eyes are on China — which has not given a firm indication of whether it will again wield its veto.

"My suspicion is that (China) will not budge despite American pressure and India's entreaties. It considers its alliance with Pakistan to be far too important," said Sumit Ganguly, an Indiana University professor of political science.