More than 17,500 people have died so far in the 7.8-magnitude earthquake that struck Turkey and Syria on Monday, and the toll is expected to rise as rescuers comb the rubble for survivors.

"Economic losses are hard to estimate as the situation is evolving, but they appear likely to exceed" $2 billion and could reach $4 billion "or more", Fitch Ratings said.

Insured losses will be much lower, possibly around $1 billion, due to low insurance coverage in the area, it added.