US firm Shearman & Sterling has struck an alliance with Saudi Arabian practice Abdulaziz Al-Assaf as Shearman seeks to build a local presence in the country.

The deal with Riyadh-based Abdulaziz, which has 16 lawyers, gives Shearman a presence in a second Middle Eastern jurisdiction alongside its existing base in Abu Dhabi, which it launched 40 years ago. The firm lists 16 lawyers in its Abu Dhabi office, including five partners.

Under the alliance agreement Shearman can now provide legal support to its clients from Abdulaziz's three bases in Riyadh, Jeddah and Al Khobar.

Creighton Condon, senior partner at Shearman, said the tie-up would "reinforce" the firm's "market-leading position throughout the Middle East".

The US firm has already worked on key mandates in the region. In 2011 it advised Dow Chemical on its joint venture with Saudi Arabian Oil Company to build a $20bn (£12.7bn) petrochemical plant at the Arabian Gulf port of Jubail.

In 2007 the firm acted for Saudi Basic Industries Corporation on its $11.6bn (£7.4bn) acquisition and related financing of resin business GE Plastics, a subsidiary of US financial services company General Electric.

DLA Piper is also planning to open a third office in the region in Al Khobar, in the eastern province of Saudi Arabia, after Ramadan, which runs until 17 July. The firm already has bases in Jeddah and Riyadh.

Elsewhere in the region, law firms are reducing their footprint. Earlier this month Herbert Smith Freehills announced that it was set to close its Abu Dhabi office.

In March Latham & Watkins revealed that it would shut its Abu Dhabi and Doha bases, leaving it with just two offices in the region, in Dubai and Riyadh.

The firm's move was followed a couple of months later with the news that fellow US outfit Baker Botts had withdrawn from Abu Dhabi at the start of 2015.