- The pan-European Stoxx 600 recouped earlier losses during Tuesday afternoon.
- President Donald Trump is expected to make a statement on the future of an international nuclear agreement. The incumbent has frequently threatened to withdraw the U.S. from the Iran deal in the past.
- Oil prices have fallen sharply in afternoon trade as investors speculated that Trump may opt to stay in the pact.
European markets closed mixed Tuesday, as investors eagerly awaited critical news surrounding the Iran nuclear accord.
The pan-European Stoxx 600 closed provisionally around 0.1 percent higher Tuesday, with most major European bourses in negative territory.
The FTSE 100 index closed almost unchanged, Germany's Dax lost 0.29 percent of its aggregate value, while the French CAC-40 closed lower by 0.21 percent.
Italian equity investors were the big losers as uncertainty over the country's future government loomed. The FTSE MIB in Milan closed down by 1.67 percent.
On a stock basis, Shire finished near the top of the European benchmark, gaining almost 5 percent. Japan's Takeda Pharmaceutical has struck a deal to buy the Irish drugmaker for £46 billion. The agreement ends a takeover battle that had seen Takeda make five offers for UK-listed Shire since late March.
Fellow drugmaker Lundbeck surged to the top of the European benchmark after it reported better-than-expected earnings in the first three months of 2018. The Danish company said sales of its schizophrenia and depression drugs helped offset the generic competition of its older products. Shares were more than 8 percent higher by the end of trade.
Meanwhile, Europe's travel and leisure stocks were one of the few sectoral gainers, up 0.3 percent amid earnings news. British bookmaker William Hill was a decent performer after it posted its latest figures for the first 17 weeks of the year. The firm said Roma's shock defeat of Barcelona and an uptick in U.S. March Madness college basketball betting helped drive a 12 percent rise in profits. Its shares finished up 0.61 percent on the news.
Danish hearing aid maker William Demant tumbled to the bottom of the European index after a first-quarter growth warning. It said lower demand by the U.K.'s National Health Service was a drag on overall growth over the first three months of the year. Shares of the Copenhagen-listed firm finished nearly 10 percent lower on the news.
After oil prices climbed to fresh highs Monday, the energy market pared back its gains on Tuesday as political news curbed sentiment. On Tuesday afternoon, crude futures fell into the red with U.S. WTI and Brent both dropping more than $3 per barrel to hit session lows.
Prices were under pressure as the market grew nervous over an announcement by the U.S. administration, concerning the Iran nuclear deal.
President Donald Trump is expected to make a statement on the future of an international nuclear agreement. In the past, the incumbent has frequently threatened to withdraw the U.S. from the deal — which lifted sanctions on Iran in return for the country to pull back on its nuclear ambitions — unless nations in Europe that took part in the accord, amend what Trump sees as weak points of the deal.
Despite Trump's threats to withdraw, President Hassan Rouhani stated that Iran had a plan to counter any move made by Trump when it comes to the 2015 agreement; Reuters reported. The U.S. leader is widely expected to pull out from the agreement, however Rouhani said Sunday, that this would be "making a mistake."
Finally, Comcast is looking into a $60 billion all-cash bid to surpass Walt Disney on its deal to acquire the majority of Twenty-First Century Fox's assets — if the U.S. government goes on to approve the acquisition of Time Warner by AT&T, people familiar with the matter have revealed. The U.S. broadcaster has also got plans to acquire the whole of Britain's broadcast firm, Sky, as part of an improved all-cash bid.
—CNBC's Alex Sherman contributed to this report
Disclosure: Comcast is the owner of NBCUniversal, parent company of CNBC and CNBC.com.