Is the interrupt handler in the Atmega Attiny13 interrupted by another interrupt?

Question

Microcontrollers

Hello!
The program on the ATTINY13A microcontroller uses timer, comparator and pin changed interrupts (difficult to translate). When we are inside one interrupt handler, can other interrupts interrupt the process of its processing? Should I do CLI and then SEI or is it optional?
Thank you!

Answer 1

How about at least looking through the datasheet or easyelectronics?
When entering the handler, all interrupts are blocked, so if you do not do sei in the handler (there are craftsmen), no one will interrupt it. When reti is called, interrupts are enabled in place.