When Mohammed Sweirky prepared to leave for a work trip in January to repair telecommunications infrastructure that had been destroyed in northern Gaza, his wife and children pleaded with him not to go.

Fighting between Israeli troops and Hamas members was still raging in the area, said Mr. Sweirky, who is a technician for Paltel, the largest telecommunications company in Gaza, and his family worried he might not return. But he said he felt he had no choice given that residents there desperately needed their phone services restored.

“It was painful to say bye,” said Mr. Sweirky, 50, who fled Gaza City at the beginning of the war and is now sheltering with six family members in a garage in Rafah, the territory’s southernmost city. “They were crying, but I couldn’t abandon our mission.”

Since the start of the war, Mr. Sweirky’s job has become among the most dangerous in Gaza and also one of the most important. Israel’s bombing campaign against Hamas has pummeled telecommunications infrastructure in Gaza, destroying subterranean fiber cables, damaging data centers and blowing up cell towers.

Since the war began, some 50 engineers and technicians at Paltel, one of two Palestinian cell service providers in Gaza, have crisscrossed the enclave to reinstate service in neighborhoods that have been plunged into blackouts for days and even weeks.

Paltel — which is dependent on three telecommunication lines that pass through Israel — operates infrastructure in Gaza. Trying to repair that infrastructure has entailed enormous risks for Paltel technicians, who often have to work near battles and who say they have also come under fire.