Oil prices inched higher on Tuesday, with Brent crude surging past the $90-a-barrel mark as hopes of an early end to the Middle East war remained uncertain. Iran signalled a shift towards a more offensive military approach, while US ruled out extending the ceasefire, adding to concerns over the conflict’s impact on energy supplies.Around 7:30 am IST, WTI crude was trading at $84.84 a barrel, up 34 cents or 0.40%, after gaining more than 1% earlier in the session to $85.37, its highest level since July 31. Brent crude stood at $91.08 a barrel, up 21 cents or 0.23%, after rising to its highest level since July 30 on Monday.The prospects of renewed peace talks and a return of oil tanker traffic through the Strait of Hormuz have stalled.A senior Iranian official told Reuters on Monday that Iran would move to a “fully offensive” military posture as attempts to negotiate a permanent end to the war with the US had stalled. Washington has also ruled out extending the temporary ceasefire agreement.The impact on shipping through the Strait of Hormuz has become increasingly visible. Kpler’s ship-tracking data showed that just five commodity vessels passed through the strait on Saturday following attacks on tankers, while none were registered on Sunday. The previous weekend had seen 31 vessels transit the waterway, Reuters reported.Tensions have also spread to the Red Sea.Yemen’s Houthis attacked what they described as a Saudi military ship along with four escort vessels using missiles, according to the group’s military spokesperson Yahya Saree on Telegram.At the same time, Iran has been holding separate negotiations with Oman over an agreement to manage the Strait of Hormuz and said the two sides were close to reaching a deal. Trump responded by threatening to bomb Oman, which is a longstanding US security partner.There were some signs that diplomatic efforts could still continue, however, as media reports said Trump had begun back-channel discussions with the Islamic Revolutionary Guard Corps.