(Reuters) -U.S. stock index futures rose on Tuesday as President Donald Trump announced a ceasefire between Israel and Iran, bringing investors some relief after 12 days of conflict in the Middle East hurt global risk assets and fanned inflation concerns.

Oil prices dropped to their lowest levels in two weeks as supply concerns triggered by the war eased, pulling down U.S. energy stocks in premarket trade. Chevron and Exxon were down 1% and 1.7%, respectively.

Defense stocks Lockheed Martin and RTX Corp dipped about 1.6% each.

Trump's call for truce was a sharp turnaround after the U.S. bombed Iran's nuclear sites over the weekend and Iran retaliated by firing missiles at a U.S. base in Qatar.

Hours after the ceasefire declaration, however, Israeli Defence Minister Israel Katz said Iranian missiles were fired in violation of the agreement and he had ordered the military to strike Tehran in response. Iran said it had not violated the ceasefire.

For the moment, optimism around the ceasefire was helping support equities.

At 05:26 a.m. ET, Dow E-minis were up 326 points, or 0.76%, S&P 500 E-minis were up 53.5 points, or 0.88%. Nasdaq 100 E-minis were up 252.75 points, or 1.15%.

The benchmark S&P 500 index remains about 2% below its record level.

Federal Reserve Chair Jerome Powell's congressional testimony scheduled at 10:00 a.m. ET will likely be parsed for clues regarding the near-term interest rate trajectory, a day after policymaker Michelle Bowman said a cut as soon as July could be a possibility.

Six central bank officials including Fed Board Governor Michael Barr and Fed Minneapolis President Neel Kashkari are also scheduled to speak later in the day.

This week, focus will be on the Commerce Department's final take on first-quarter GDP and its Personal Consumption Expenditures (PCE) data.

Consumer confidence data for June is due at 10:00 a.m. ET.

Megacap and growth stocks were trading higher, with Tesla shares leading gains, up 2.7%. Google-parent Alphabet rose 1.5% while Amazon.com was up 1.8%.

Shares of crypto companies rose after bitcoin hit a one-week high. Coinbase Global was up 3.2% and Strategy advanced 1.8%.

Package delivery firm FedEx was up nearly 1% ahead of quarterly results due after the closing bell.

(Reporting by Kanchana Chakravarty in Bengaluru; Editing by Devika Syamnath)