Commercial airlines around the world on Monday were weighing how long to suspend Middle East flights after the U.S. struck Iran.

Singapore Airlines, one of the highest-profile in Asia, called the situation "fluid" on Sunday as it canceled flights from Singapore to Dubai following a security assessment.

The Mideast route has become more important for flights between Europe and Asia since Russian and Ukrainian airspace closed due to war, but flight tracking website Flightradar24 showed empty space over Iran, Iraq, Syria, and Israel.

Air France KLM said it canceled flights to and from Dubai and Riyadh on Sunday and Monday.

British Airways also canceled flights to and from Dubai and Doha for Sunday. It was still reviewing the situation, it said in a statement that evening when asked about later flights.

Missile and drone barrages in a growing number of conflict zones represent a high risk to airline traffic, and an organization that monitors flight risks, Safe Airspace, warned on Sunday that U.S. attacks on Iran's nuclear sites could heighten the threat to American operators in the region.

In the days before the U.S. strikes, American Airlines suspended flights to Qatar, and United Airlines did the same with flights to Dubai.

Airlines are also concerned about a potential spike in oil prices following the U.S. attacks, which will increase the cost of jet fuel.

Israel, meanwhile, is ramping up flights to help stranded travelers at home and abroad. The country's Airports Authority said rescue flights to the country would expand Monday with 24 a day, although each flight would be limited to 50 passengers.

Israeli airline El Al on Sunday said it received applications to leave the country from about 25,000 people in one day.