CMS has closed its Iran office just over two years after becoming the first international law firm to move into the country.

The firm opened in Tehran in February 2016, weeks after sanctions on the country were lifted in the wake of the landmark international agreement to limit its nuclear activities.

However, President Donald Trump pulled the US out of the deal in May last year, reimposing the previous sanctions, with CMS opting to close its base in the Navak Tower as a result.

The office had been staffed by lawyers from the firm's German arm, CMS Hasche Sigle, including corporate partner Jurgen Frodermann and German-Iranian energy partner Shaghayegh Smousavi, both of who have now returned to the firm's Duesseldorf base.

CMS had considered a move into Tehran for some time, setting up an Iran taskforce in 2013 after the election of president Hassan Rouhani and the start of the negotiations over the nuclear deal. The sanctions on Iran were lifted on 16 January 2016, with the office opening at the start of February.

Dentons also took steps into the Iran market in 2016, agreeing an association with Tehran firm Arman Pirouzan Parvine Legal Institute, which now operates as APP in association with Dentons.

However, while the association remains in place, all references to the relationship have been removed from the Dentons website. The firm's Iran team leader, corporate partner Pirouzan Parvine, is based full-time in Paris.

In a statement, the firm said it reviewed all communications relating to its associate relationships "in light of new events as needed", adding: "Dentons does not have operations in Iran. APP is a separate and independent law firm, with an associate firm relationship with Dentons Europe LLP."

Other firms to have made moves into Iran since the sanctions were lifted include France's Gide Loyrette Nouel, which opened a Tehran office in 2017 headed by international trade and regulatory partner Mehrnoosh Aryanpour, who joined from Gibson Dunn & Crutcher.

While the office remains in operation, all references to it have been removed from the Gide website, a move the firm said had been taken as it is "no longer actively prospecting in Iran". According to the Gide website, Aryanpour is now based in Paris.

In a statement, the firm said it was "currently investigating the different options to serve our clients which are active in this country, in full compliance with the regulatory context of international sanctions", adding that no definitive decision had yet been taken.