Alexandra Gibbs, CNBC–

U.S. stock index futures fluctuated ahead of Tuesday’s open, as markets around the world turned their attention to the U.S. administration and the future of the country’s involvement in the 2015 nuclear accord with Iran.

Around 4:20 a.m. ET, Dow futures slipped 21 points, indicating a lower open of 19.32 points. The Nasdaq and the S&P 500 futures indicated a relatively flat to lower start to the session for their respective markets.

The moves in pre-market trade come as global markets remain on edge, awaiting an announcement by President Donald Trump on the future of an international nuclear agreement.

In the past, Trump has often threatened to withdraw the U.S. from the Iran deal — which lifted sanctions on the Middle Eastern nation, in return for the country to pull back on its nuclear ambitions — unless allies in Europe amend what he sees as shortcomings of the agreement.

In spite of the U.S. incumbent’s threats to pull out, President Hassan Rouhani stated that Iran had a plan to counter any move made by Trump when it comes to the deal; Reuters reported. While it is widely expected that the U.S. president will withdraw the country from the accord, Rouhani said Tuesday that Iran would continue to seek “constructive relations with the world,” despite potential sanctions.

In Asia, markets finished the session on a mostly positive note, while in Europe, stocks were under slight pressure during trade.

Aside from turbulence in the political space, earnings continue to flood in this week. On Tuesday, JD.com, Discovery, Camping World, Crocs, Dean Foods, SeaWorld, Disney, Electronic Arts, Marriott, Match Group, Etsy, GoDaddy, Papa John’s and Wendy’s are just a handful of names set to publish their latest financial results.

In central banking news, Fed Chair Jerome Powell delivered remarks in Zurich Tuesday. At the Swiss National Bank and International Monetary Fund’s High Level Conference, the chair of the U.S. central bank said that the Fed’s interest rate hikes may not end up having as great of a risk on emerging market economies and stock markets as many had initially thought.

Powell added that the central bank would however continue to communicate its policies clearly, to avoid market disruptions.

On the economic front, the NFIB Small Business Optimism Index is scheduled to be released at 6 a.m. ET, followed by the Job Openings and Labor Turnover Survey (JOLTS) at 10 a.m. ET.