Longtime Vinson & Elkins energy partner and former China practice head Xiao Yong has left the firm to join Dechert.

Xiao will join with an additional team of lawyers, all who specialize in energy work. Xiao and associate Jason Wu will be based in Dechert’s Hong Kong office, while partner Nicholas Song, counsel Zhaohui Li and associate Sarah Teh are joining the firm in Beijing.

The move is subject to partnership vote next week.

A former government official, Xiao represents state-owned enterprises on outbound oil and gas deals and projects. In late 2015, Xiao led the Vinson & Elkins team representing longtime client China Petrochemical Corp., or Sinopec, on a $1.3 billion deal to buy a 10 percent stake in Russian energy company Sibur. In addition to Sinopec, he has advised China National Offshore Oil Corp., or CNOOC, and China National Petroleum Corp. on deals in the Americas and Southeast Asia.

Xiao joined Vinson & Elkins in 1997 from Skadden, Arps, Slate, Meagher & Flom where he was counsel. He made partner five years later and has led the firm’s China practice ever since. Before joining Skadden in 1995, Xiao spent a decade as a senior official of the foreign investment law division at China’s Ministry of Foreign Trade and Economic Cooperation, now known as the Ministry of Commerce.

The departures follow an already sharp decline in Vinson & Elkins’ Asia head count over the past five years. The Houston-based firm reported as many as 40 lawyers in Asia in 2012, but only 15 in 2015. Once the go-to firm for China’s oil giant’s overseas projects , Vinson & Elkins has seen a drop in demand for that type of work as state-owned enterprises cut back on outbound activity. The global dip in oil prices since 2014, coupled with a big Chinese anti-corruption campaign, significantly reduced the size and number of large overseas deals by CNPC, Sinopec and CNOOC alike.

A Houston-based Vinson & Elkins spokeswoman said the firm conducted a strategic review last year for the Hong Kong and Beijing offices and decided to realign its China practice to be more consistent with the global strategy. The two offices will now focus on such practices as private equity and special situations, energy projects for global clients, international dispute resolution, governmental investigations and intellectual property.

Vinson & Elkins opened a fourth Asian office in Taipei last year, focusing on intellectual property and technology work. In 2013, the firm closed its Shanghai office to focus on Beijing-based state-owned enterprise clients. Former Shanghai managing partner David Blumental, who joined the firm along with Xiao from Skadden, left for Latham & Watkins the following year . The firm also canceled a plan to reopen a Singapore office in 2014 as the price of oil dropped.

Last year, partners James Cuclis and David Lang both relocated to Houston from Hong Kong.