U.S. stock futures jumped in early European trade as artificial-intelligence stocks rode a fresh wave of optimism, buoying indexes in Asia and Europe. Nasdaq futures were 1.1% higher following gains for chip stocks in Korea, Japan and China. Earnings releases from Alphabet and Tesla on Wednesday could give clearer direction to yo-yoing tech stocks.

Meanwhile, oil prices hovered close to $90 a barrel as traders weighed competing developments. Mediators' push for a new ceasefire between the U.S. and Iran encouraged markets, but a promised Houthi blockade on Saudi Arabia and President Trump's commitment to make Iran pay "many times over" kept the risk premium intact. Brent crude was down 1% to $88.32 a barrel, while WTI futures slipped 0.7% to $81.91.

In the U.S., futures for the S&P 500 were up 0.5% while the Dow Jones Industrial Average rose 0.3%. Chip stocks looked set to rally, with Micron Technology gaining 5.1% in after-hours trade while Intel jumped 4.5%.