Traveling to Hanoi and stopping in Xiamen for Transit

I'm hold an El Salvador passport and I'll travel to Vietnam in a couple weeks. One of my stops is in Xiamen in a flight coming from Amsterdam. My flight from Xiamen to Bangkok has a 3 hours and 55 minutes layover in Xiamen. Would I need a special kind of Visa, or am I able to apply for the 24 hour transit permit? Thanks!