The administration of President Donald Trump is calling for the Group of 20 to drop its long-standing commitment to free trade and opposition to protectionist policies.
The formal statement issued after the meeting contained only a bland reference to "working to strengthen the contribution of trade to our economies".
Ahead of a G20 finance minister meeting in Germany, "friendly and constructive" talks with his Berlin counterpart, Wolfgang Schäuble, marked Mr Mnuchin's first outing since taking office.
Angel Gurria, secretary-general of the Organization for Economic Cooperation and Development, downplayed differences over the language.
Speaking to Reuters ahead of the meeting, Schäuble said the protectionist stance of the new US administration could complicate the talks and force policymakers to leave out the disputed trade issue. The OECD is one of several global organizations invited to participate in the meeting.
Last year, the group of the world's 20 largest economies vowed to "resist all forms of protectionism". Possible replacements include support for "fairness".
The Trump administration has criticized China, Japan and Germany over their foreign currency policies.
The gathering Friday and Saturday in the southern German resort town of Baden-Baden will help set the tone for global commerce and finance and will give Mnuchin a chance to clarify what the USA position is.
During the meeting in Baden-Baden, European countries and China were said to be pushing for a stronger stance in favour of free trade and cooperative, multi-country frameworks for trade such as the World Trade Organisation.
"I regret that our discussions today were unable to reach a satisfying conclusion on two absolutely essential priorities that our world and which France would have liked to see the G20 continue to take firm and concerted action on", said French Finance Minister Michel Sapin. The finance ministers' meeting will pave the way for a July 7-8 summit of national leaders in Hamburg, Germany.
Trump, whose tough "America First" talk helped win him the presidency, has withdrawn the USA from a trans-Pacific free trade pact and attacked export giants China and Germany.
Trump has suggested global warming was a "hoax" concocted by China to hurt US industry and vowed to scrap the Paris climate accord aimed at curbing greenhouse gas emissions.
Others suggested that the G20 leaders' meeting in Hamburg this July could be the real opportunity to bring the USA on board.
G20 financial leaders, however, reaffirmed their a commitment to refrain from competitive currency devaluation, a key agreement as the US has repeatedly complained that some of its trade partners are using artificially devalued currencies to gain a trade advantage.
"There is a lot of pressure at this meeting to get leaders on the same page on trade", said LeCompte. "But the pace of growth is still weaker than desirable and downside risks for the global economy remain".
Trump, whose tough protectionist talk helped win him the presidency, has withdrawn the USA from a trans-Pacific free trade pact and attacked export giants China and Germany.
Advocates for free trade such as the International Monetary Fund say that trade restrictions will only hurt growth and won't benefit ordinary people, while urging measures to spread the benefits of trade more widely. Those could include targeted job training and education.