Commercial airlines around the world are weighing how long to suspend Middle East flights as conflict in the region enters a new phase.

The usually busy airspace stretching from Iran and Iraq to the Mediterranean has been largely empty of commercial air traffic for 10 days since Israel began strikes on Iran on June 13.

Airlines have diverted, cancelled and delayed flights through the region due to airspace closures and safety concerns.

Further cancellations of some flights by international carriers in recent days to usually resilient aviation hubs such as Dubai, the world’s busiest international airport, and Qatar’s Doha, show how aviation industry concerns about the region have escalated.

However, some international airlines resumed services on Monday.

Leading Asian carrier Singapore Airlines, which described the situation as “fluid”, was to resume flying to Dubai on Monday after cancelling its Sunday flight from Singapore.

Flightradar24 departure boards show British Airways, owned by IAG, was also planning resume Dubai and Doha flights on Monday after cancelling routes to and from those airports on Sunday.

Air France KLM cancelled flights to and from Dubai and Riyadh on Sunday and Monday.

With Russian and Ukrainian airspace also closed to most airlines due to years of war, the Middle East has become a more important route for flights from Europe to Asia and Australia. However, amid missile and air strikes during the past 10 days, airlines have routed north via the Caspian Sea or south via Egypt and Saudi Arabia.

Added to increased fuel and crew costs from these long detours and cancellations, carriers also face a potential hike in jet fuel costs as oil prices rise following the US attacks.

Safe Airspace, a website run by OPSGROUP, which shares flight risk information, noted on Sunday that US attacks on Iran’s nuclear sites could raise the threat to American operators in the region.

In the days before the US strikes, American Airlines suspended flights to Qatar, and United Airlines and Air Canada did the same with flights to Dubai. They have yet to resume.

Israel is ramping up flights to help people return home, and leave. Its Airports Authority said so-called rescue flights to the country would expand on Monday with 24 a day, although each flight would be limited to 50 passengers.