Russian Prime Minister Vladimir Putin (R) speaks with Exxon CEO Rex Tillerson at a signing ceremony in the Black Sea resort of Sochi August 30, 2011. REUTERS/Alexsey Druginyn/RIA Novosti/Pool

President-elect Donald Trump is poised to tap ExxonMobil CEO Rex Tillerson for secretary of state, NBC News reported on Saturday.

NBC's Andrea Mitchell, citing sources, said that Tillerson will be officially nominated sometime next week, "barring some unforeseen change of mind by the president-elect."

Tillerson recently rose as one of the top contenders for secretary of state, and his reported nomination comes on the heels of former New York mayor Rudy Giuliani taking himself out of consideration for the position. Other top contenders were former military officer David Petraeus and former presidential candidate and Massachusetts governor Mitt Romney.

Though the Trump team has not yet confirmed that it has selected Tillerson for secretary of state, his potential nomination as the primary conduit between the United States and foreign governments is raising concerns among some, particularly because of his connections to the Russian government and Russian president Vladimir Putin.

Tillerson, who has no previous government experience or experience working as a diplomat, has ties to Russia that go back nearly two decades. Tillerson met Putin in 1999, according to Bloomberg, when Tillerson first represented Exxon's interests in Russia while it was under Boris Yeltsin's leadership.

Tillerson, while representing Exxon, has also worked with Rosneft, a major Russian state-run corporation, since the 1990s, when they first collaborated on the Sakhalin-1 project in Russia's Far East. Since then, the project has been successful in furthering Exxon's and Rosneft's oil interests.

In 2011, Tillerson struck another deal for Exxon with Rosneft, which gave Exxon access to oil fields in the Arctic. In return, Rosneft received stakes in a number of Exxon projects within the US. That deal eventually tanked, however, when Russia invaded Crimea and stoked tensions with Ukraine, leading the US to impose sanctions on Russia. Tillerson criticized the move sharply, citing the "broad collateral damage" the sanctions caused.

Tillerson holds a $151 million stake in Exxon stock, according to securities filings reviewed by the Wall Street Journal, and the value of that stock would increase if US sanctions on Russia were lifted. The Journal notes that as secretary of state, one of the first conflicts of interest Tillerson would need to address would be his holdings in Exxon. He would likely need to divest his interests in the company based on the State Department's ethics rules, Chase Untermeyer, a former US Ambassador to Qatar, told the Journal.

"He could not erase his strong relationship with a particular country," Untermeyer said. “The best protection from a conflict of interest is transparency."

Nonetheless, Tillerson has remained the primary branch between Exxon and the Kremlin. Under Tillerson's wing, Exxon's holdings in Russia outpaced its holdings in the US, Bloomberg reported. And when Russia strongarmed foreign investors into giving up their oil interests in a particularly lucrative territory under Russian control, Exxon's interests remained untouched.

"[Tillerson] has had more interactive time with Vladimir Putin than probably any other American with the exception of Henry Kissinger," John Hamre, a former deputy defense secretary during the Clinton administration and president of the Center for Strategic and International Studies, told the Journal. In 2013, Putin awarded Tillerson with the Order of Friendship medal; the award is bestowed upon foreigners whose work helps to better the interests of Russia and its people.

While figures across the political spectrum have expressed concern over Tillerson's potential nomination, others see it differently.

"[The] presumption that Tillerson must be a pro-Putin ideologue [because he and Exxon] did business successfully in Putin's Russia is simplistic and patronizing," tweeted Suzanne Maloney, an expert at the Brookings Institution's Center for Middle East Policy and a former Exxon employee.

She went on to say that Tillerson's business experience gives him a "deep, nuanced understanding" of political and regional dynamics, especially because he works in the oil industry. "In this sense, Tillerson's business experience gives him a very different lens than other [executives] in Trump's cabinet – and very relevant for diplomacy," Maloney continued.

"Tillerson rose to [the] top of a company that prizes technical excellence, rock-solid financials, hard work, and integrity," Maloney tweeted. "[The State Department could] do a lot worse."