A 2.8 kg preterm newborn (34 weeks) born to an Indian mother with gestational diabetes is delivered by emergency cesarean section for fetal distress. At 1 minute, the infant is pink, crying vigorously, and moving all limbs well. Heart rate is 145 bpm. APGAR score at 1 minute is 9. However, at 5 minutes, the infant becomes increasingly cyanotic despite supplemental oxygen, with grunting and intercostal retractions. Respiratory rate is 68 breaths per minute. What is the most appropriate immediate next step?