EL-ARISH, Egypt (Ma'an) -- Egyptian forces launched two offensives in the northern Sinai early Friday, security officials said.

An air campaign targeted areas outside the city of el-Arish, while other forces launched raids inside the city, officials told Ma'an.

Large numbers of soldiers and military vehicles have been deployed to combat "terrorists" in the region, the security sources said.

An Egyptian military source said that the armed forces had arrested six "terrorists" in the Sinai region, state television reported.

On Thursday residents told Reuters they were skeptical about the two-day security campaign, saying they had seen no sign of anyone being killed in what they described as a "haphazard" operation.

Army commanders said as many as 20 "terrorists" had died in the offensive launched after suspected Islamist militants killed 16 Egyptian border guards on Sunday and drove a stolen armored car into Israel which was then destroyed by Israeli forces.

But residents in Shaikh Zuwaid and surrounding villages said they had seen no sign of fighting.

In al Toumah, a village surrounded by olive fields, one witness said he saw troops firing in the air.

"We thought they were chasing someone, but their arms were directed up and we didn't see who they were fighting with," the witness, who declined to be named, said. "We couldn't find any bodies or signs of battle after they left."

In Shaikh Zuwaid, controlled by Bedouin tribal leaders since police deserted the area last year, life continued as normal, its markets bustling. Witnesses reported a military presence on the outskirts, but no fighting since Wednesday's air strikes.

The offensive is crucial to maintaining good relations with Israel, which fears Islamist militants based in the increasingly lawless desert region could link up with hardliners in neighboring Gaza to launch attacks on Israel - potentially threatening a 1979 peace treaty with Egypt.

Reuters contributed to this report