BEIJING (AP) — China's airline industry association has thrown its support behind 13 Chinese carriers seeking compensation from Boeing for groundings of the 737 Max 8.

The China Air Transport Association said in a statement Friday that the groundings and delayed deliveries of the planes were causing "serious damage" to the companies' businesses. It estimated their losses at 4 billion yuan ($580 million) should the planes remain grounded through the end of next month.

The group said it would "actively support and coordinate member companies to carry out their compensation work."

The Chinese airlines have 96 Max aircraft in their fleets, with more than 30 more due to be delivered this year.

China was among the first governments to order 737 Max jets grounded in March after crashes in Ethiopia and Indonesia.