U.S. stock futures indicate a positive open for Wall Street, with President Donald Trump’s declaration of a ceasefire in the Israel-Iran conflict bolstering sentiment -- although key questions linger over the staying power of the halt to hostilities. Oil prices drop following the announcement, while gold falls amid faltering safe-haven demand. Meanwhile, the spotlight will be on Federal Reserve Chair Jerome Powell, who will deliver testimony to Congress this week during a time when he has come under heavy criticism from Trump.

1. Futures higher

U.S. stock futures pointed higher on Tuesday, as investors welcomed Trump’s announcement of a ceasefire in hostilities between Israel and Iran.

By 03:40 ET (07:40 GMT), the Dow futures contract had risen by 347 points or 0.7%, S&P 500 futures had gained 48 points or 0.8%, and Nasdaq 100 futures had advanced by 234 points or 1.0%.

The main averages on Wall Street ended the prior session in the green, boosted by hopes that U.S. involvement in the days-long Israel-Iran air war would remain relatively contained. Worries had swirled around the prospect of U.S. strikes against Iranian nuclear sites over the weekend causing a wider conflict in the Middle East, and potentially disrupting crucial oil supplies out of the region.

Iran responded to the attacks by launching missiles at a U.S. military base in Qatar late on Monday, but no injuries were caused. Trump called the response “weak.”

2. Trump proclaims Israel-Iran ceasefire

Trump has declared that the ceasefire between Israel and Iran is now "in effect," adding that neither side should violate it.

The statement has lifted expectations that the 12-day bout of fighting that included deadly air strikes has now come to an end.

However, Trump’s comments suggested that the ceasefire would take place in stages, with operations already underway being allowed to finish. An Iranian missile attack on Israel on Tuesday killed four people, according to Reuters, citing Israel’s ambulance service. Meanwhile, Tehran said an Israeli strike on northern Iran had killed nine people.

Still, questions surrounded the longevity of the ceasefire. Israel, who was joined by the U.S. in its bid to erase Iran’s nuclear and ballistic missile ambitions, said it had agreed to a halt in the violence, with Prime Minister Benjamin Netanyahu noting that the operation had achieved its objectives.

Iranian Foreign Minister Abbas Araqchi also said Tehran had no intention of continuing its retaliatory strikes moving forward, but stood ready to respond to any further aggression from Israel -- a sentiment that Netanyahu reciprocated.

3. Oil slumps

Oil prices tumbled in the wake of the ceasefire announcement, as fears eased over possible shipping disruptions out of the Middle East.

Since the outset of the conflict, traders had been eyeing concerns that Iran could move to cut off crude supplies flowing through the Strait of Hormuz, a major artery for global shipping that runs along the nation’s southern coast.

Oil had initially spiked with this possibility in mind, but began to fall after Iran’s attack on the U.S. base in Qatar was perceived as tepid and a precursor to a cooling in regional tensions.

At 03:16 ET on Tuesday, Brent crude futures slipped by 3.7% to $67.93 a barrel, while U.S. West Texas Intermediate crude futures dropped by 3.6% to $66.04 per barrel -- the lowest level since before Israel carried out its attacks on Iran earlier this month. Oil prices previously declined by 9% on Monday.

4. Gold retreats as safe-haven demand fades

Gold prices slipped over 1% in European trade, as fading geopolitical tensions prompted investors to shift away from safe-haven assets.

Spot gold declined 1.4% to $3,320.57 an ounce by 03:25 ET, dipping to its lowest level since June 11. Gold futures for August dropped 1.8% to $3,334.87/oz.

Meanwhile, news of the ceasefire put the U.S. dollar on the back foot, with an index tracking the currency against a basket of its peers inching down by 0.4% to 98.06.

The euro and the yen strengthened, buoyed by the slide in oil prices. Both the European Union and Japan rely on imports of crude, while the U.S. is a net exporter.

Benchmark 10-year Treasury yields were also broadly steady after edging lower on Monday following comments from a Federal Reserve official backing an interest rate reduction next month. Yields tend to move inversely to prices.

5. Powell testimony ahead

Markets are now turning their focus from the Middle East to Washington, where Federal Reserve Chair Jerome Powell is due to begin two days of testimony before Congress on Tuesday.

Powell will likely be grilled on the Fed’s decision to keep rates unchanged at its latest meeting and adopt a wait-and-see attitude to future borrowing cost changes. Policymakers, including Powell, have been especially wary of the uncertainty surrounding the impact of Trump’s aggressive tariff agenda.

Trump continued his ongoing campaign against Powell on Tuesday, writing on social media that Powell is a "very dumb, hardheaded person." He called for rates to be brought down by at least "two to three points," arguing that the U.S. will pay for Powell’s "incompetence."

"Crucially, markets may treat any tweaks in Powell’s stance as an indication that Trump’s political pressure has breached the independence shield of the Fed," analysts at ING said in a note to clients, adding that this "has the potential to drive substantial [U.S. dollar] depreciation."