ISMAILIA, Egypt - Egypt's military is deploying light armored vehicles in Sinai to replace some heavy tanks whose presence at the border area had raised concerns in Israel, security sources said on Tuesday.A source said last week the army had begun withdrawing some of the tanks, after they had been deployed as part of an operation against militants who attacked and killed 16 border guards on Aug. 5. Disorder has spread in Sinai since former President Hosni Mubarak's overthrow last year. Analysts say Islamists with possible links to al-Qaida have gained a foothold, which has alarmed Israel.The unrest has occurred mainly in North Sinai, where many people have guns and where Beduin tribes have long complained of neglect by central government. They say they have seen no benefits from the expanding Sinai tourist resorts.Hundreds of troops, along with tanks, armored vehicles and helicopters were sent to the area in a joint operation with police to raid militant hideouts, arrest suspects and seize weapons, including rockets and other arms, rife in the area.But Israeli officials have privately voiced concerns about heavy equipment being sent to areas where there have been restrictions on weapon deployments under a 1979 peace treaty, the first such treaty reached between Israel and an Arab state."Twenty tanks have been withdrawn from the central sector of Sinai toward Suez," a security source said, adding that about 20 armored vehicles have reached Al-Arish city, the administrative center of North Sinai.The sources did not give a clear answer to whether the withdrawal of tanks was taken in response to Israel's concerns or say how many tanks were still in Sinai.The army said last week it would broaden its campaign in Sinai, involving a redeployment of forces but did not specify which areas they would redeploy to."The operation is entering a new phase that requires different equipment capable of facing and handling the situation in Sinai," a military official told Reuters on Tuesday.Another security source said the tanks were removed to be replaced with more "useful equipment."Analysts said there was no doubt that the tanks were taken out to assuage Israeli concerns. "Egypt's decision to remove tanks was taken to calm Israel after it voiced concerns about the presence of tanks near its borders," Safwat al Zayaat, a retired army general and military expert said."As if the tanks were, as Egypt is saying now, not useful then why did it send them there in the first place?" he said.A security source said security forces defused a land mine and a bomb on Tuesday planted by militants east of Al-Arish. It was the fourth such incident since last week.No one had yet claimed responsibility for the killing of the border guards on Aug. 5. But a Sinai-based Islamist militant organization, the Salafi Jihadi Group - which denies any involvement in the border attack - warned the Egyptian army that the crackdown would force it to fight back.