ExxonMobil Corp. on Thursday said it would fight a $2 million fine imposed by the U.S. Department of Treasury for potentially violating Russian sanctions dating to 2014 while it was led by Secretary of State Rex Tillerson.

The business transactions occurred in May 2014, shortly after the U.S. government sanctioned Russian companies and executives for the country’s incursion into Ukraine and its annexation of Crimea, according to the complaint filed Thursday by Treasury’s Office of Foreign Assets Control (OFAC).

ExxonMobil said it was following “clear guidance” from the Obama administration at the time and accused the Treasury office of acting based on a later re-interpretation of the sanctions.

The sanctioned individual involved was Rosneft OAO President Igor Sechin, a former senior adviser to President Vladimir Putin, who had “shown utter loyalty” to Putin, “a key component to his current standing.”

According to Treasury, ExxonMobil entered into a business arrangement with Rosneft two weeks after the United States and the European Union said U.S. companies could no longer do business with Russian companies or executives. The Obama administration imposed additional sanctions against Russian entities in September 2014, followed by more stringent Treasury sanctions.

In assessing the fine, the OFAC said the presidents of U.S. subsidiaries ExxonMobil Development Co. and ExxonMobil Oil Corp. in 2014 “dealt in services of an individual whose property and interests in property were blocked,” referring to Sechin.

ExxonMobil “demonstrated reckless disregard” for the sanctions, according to the OFAC. The “senior-most executives knew of Sechin’s status” and ExxonMobil “caused significant harm to the Ukraine-related sanctions” by engaging in the business agreement. OFAC determined ExxonMobil did not voluntarily self-disclose the violations, which constituted “an egregious case.”

Whether Tillerson played a role in the business dealings was not indicated.

The sanctions against Sechin and other Russian firms and executives were imposed by Treasury on April 28, 2014, when it said “transactions by U.S. persons or within the United States involving the individuals and entities designated today are generally prohibited.” Besides Rosneft, the four other listed Russian energy companies sanctioned are Gazprom, Gazprom Neft, Lukoil and Surgutneftegas.

ExxonMobil signed documents with Sechin two weeks after the sanctions were imposed, Treasury claims.

ExxonMobil does not deny that it entered into the agreement with Rosneft, but it said guidance from the Obama administration at the time allowed the arrangement.

The company, which said it had been following “clear guidance” from the Obama administration at the time, is challenging the fine in U.S. District Court for the Northern District of Texas, Dallas Division [No. 3:17-cv-1930].

“OFAC seeks to retroactively enforce a new interpretation of an executive order that is inconsistent with the explicit and unambiguous guidance from the White House and Treasury issued before the relevant conduct and still publicly available today,” ExxonMobil’s filing stated.

The action “is fundamentally unfair and constitutes a denial of due process under the Constitution and violates the Administrative Procedure Act because market participants, including ExxonMobil, did not have notice of the interpretation OFAC now seeks to retroactively enforce.”

OFAC claims ExxonMobil violated sanctions when it signed certain documents in May 2014 that were countersigned on behalf of Rosneft by Sechin acting in his official capacity as a Rosneft executive.

“OFAC has acknowledged that White House and Treasury Department officials repeatedly said sanctions involving Sechin applied only to his personal affairs and not to companies that he managed or represented,” ExxonMobil said.

The company posted a timeline, including an Obama administration fact sheet dated March 17, 2017 which said, “Our current focus is to identify these…individuals and target their personal assets, but not companies that they may manage on behalf of the Russian state.”

The White House position “was confirmed on May 16, 2014 by a Treasury Department spokesperson, who said by way of example that BP’s American CEO was permitted to participate in Rosneft board meetings with Sechin so long as the activity related to Rosneft’s business and not Sechin’s personal business.”

BP plc, headquartered in London, also has extensive business ties with Russian oil companies, including Rosneft.

ExxonMobil claims that in July 2014 it was contacted by OFAC, which indicated it was formulating a separate policy. “Nearly a year later, in June 2015, OFAC notified ExxonMobil through a pre-penalty notice that it had violated guidance that had not been developed when the alleged offenses took place,” according to the filing.

The company said it “followed the clear guidance from the White House and Treasury Department when its representatives signed documents involving ongoing oil and gas activities in Russia with Rosneft — a nonblocked entity — that were countersigned on behalf of Rosneft by Sechin in his official capacity. At the time of the signing, those activities themselves were not under any direct sanction by the U.S. government.”

ExxonMobil has extensive investments with Rosneft. They formed a joint venture in 2011 to share technology and to explore and develop projects around the world, including in the deepwater Gulf of Mexico (GOM) and U.S. onshore, western Siberia, and offshore blocks in the Arctic Ocean and the Kara and Black seas. Additional agreements were secured in 2012, giving ExxonMobil expanded access in Russia’s offshore fields and Rosneft its first investments in North American oil and gas fields.

In 2013, in exchange for ExxonMobil’s increased access to Russia’s offshore fields, Rosneft was offered a 25% stake in the ExxonMobil’s natural gas project in Point Thomson, AK. The joint venture partners at the time also signed a separate memorandum of understanding to study the economic viability of liquefied natural gas development in the Russian Far East. Shortly thereafter, Rosneft bought a 30% stake in 20 deepwater GOM blocks held by ExxonMobil.

During ExxonMobil’s annual meeting in 2014 — two months before the initial sanctions were imposed — Tillerson suggested any sanctions wouldn’t jeopardize the partnership. He said at the time there had been “no impact on any of our plans or activities at this point, nor would we expect there to be any, barring governments taking steps that are beyond our control that we can’t do anything about. In terms of our view of country risk — our view of the geopolitical risk, and [our] ability to manage…things like sanctions, which have affected us before — we don’t see any new challenges out of the current situation.”