PARIS — G7 countries will release up to 100 million barrels of oil and diesel from strategic reserves over four months, coordinated by the International Energy Agency, with diesel deliveries concentrated in the first 20 days. The decision comes as crude prices trade at around $104 to $108 per barrel because of the war involving Iran that began in February. In Nigeria, petrol prices have risen to nearly N1,500 per litre in some places.