JERUSALEM, March 31 — Hamas, the dominant faction in the Palestinian government, is building its military capacity in the Gaza Strip, constructing tunnels and underground bunkers and smuggling in ground-to-air missiles and military-grade explosives, senior Israeli officials say.
The officials, including a top military commander who spoke in an interview on Friday, said that Hamas had learned tactics from Hezbollah, the Lebanese militant group, which brought in and stored thousands of rockets in bunkers near the northern Israeli border before its war with Israel last summer.

