The IBEX 35 opened Tuesday with little change following the previous session's gains, in a session dominated by renewed tensions in the Middle East. Fresh US airstrikes in southern Iran have dashed hopes for an imminent resolution to the conflict, driving oil prices higher.

The month of May, now entering its final stretch, has been particularly volatile, shaped by the constant ebb and flow of expectations regarding a deal to end the war involving the United States, Israel, and Iran. Despite this climate of uncertainty, the Spanish benchmark has accumulated a gain of around 3.5% for the month, even as the Strait of Hormuz remains blocked, impacting the fossil fuel trade.

The catalyst for the renewed doubts was the confirmation that US forces carried out strikes in southern Iran in what Washington described as a defensive action. This occurred while Tehran's chief negotiator and Foreign Minister were in Doha for talks with the Qatari Prime Minister regarding a potential pact to end the three-month-old war.

US Secretary of State Marco Rubio stated that reaching an agreement with Iran could 'take a few days', ruling out any immediate resolution. Brent crude futures responded by climbing more than 2% in Asian trading to 98.21 dollars per barrel.

Debt markets remained largely stable following last week's sell-off, which was fueled by fears that elevated energy prices could reignite inflation and force central banks to hike interest rates.

On the macroeconomic front, the day offers few major indicators, shifting investor focus toward Thursday. That session will see the release of Eurozone economic confidence indices and the US Private Consumption Expenditures (PCE) deflator, the Federal Reserve's preferred inflation gauge. Both data points will be crucial in assessing economic trends amid growing concerns over price spikes stemming from the Middle East conflict.

These concerns were echoed in remarks by Isabel Schnabel, a member of the European Central Bank's Governing Council. She argued that the institution should raise rates in June even if peace negotiations with Iran reach a conclusion, given that the conflict has lasted much longer than anticipated and high energy prices are permeating the broader economy.

The session also sees the return of Wall Street and the London Stock Exchange, which were closed on Monday for holidays. Analysts at Bankinter noted in their morning commentary that 'it is logical for the tone to be somewhat better in NY today, as it must catch up with the gains recorded yesterday in Europe. In Europe, the tone of the session will be more neutral/sideways, given the lack of catalysts and pending further news on the geostrategic front'.

At 0705 GMT on Tuesday, the Spanish IBEX 35 was up 10.30 points, or 0.06%, at 18,397.70 points, while the FTSE Eurofirst 300 index of leading European shares edged down 0.01%.

For the month as a whole, the IBEX 35 has gained 3.47%.

In the banking sector, Santander lost 0.35%, BBVA fell 0.05%, Caixabank edged up 0.04%, Sabadell gained 0.69%, Bankinter rose 0.17%, and Unicaja Banco climbed 0.21%.

Among major non-financial stocks, Telefónica fell 0.64%, Inditex shed 0.16%, Iberdrola gained 1.06%, Cellnex dropped 0.24%, and the oil major Repsol rose 0.18%.

(Reporting by Tomás Cobos; editing by Benjamín Mejías Valencia)