IDF forces on Saturday pressed ahead with a ground operation in the Gaza Strip, where Palestinian militants kept firing rockets deep into Israel's heartland.Tanks were positioned in the morning near the border with Gaza, on the second day of the land campaign.A rocket launched from Gaza landed in an open area near Kiryat Malachi mid-morning Saturday as a fresh volley of projectile were launched at Israel, Channel 2 reported. No injuries were reported. Air raid sirens sounded in southern Israeli communities on Saturday morning, including Ashdod, Gedera and Kiryat Malachi. Three IDF soldiers were wounded overnight during a confrontation with terrorists in the Gaza Strip. On Saturday morning the military confirmed that one soldier was seriously wounded and two others were lightly wounded in the incident. The wounded soldiers were evacuated to an Israeli hospital for medical treatment.US Secretary of State John Kerry was expected to arrived to Cairo on Saturday to discuss efforts to bring about a cease-fire between Israel and Hamas as the IDF's ground incursion launched Thursday night against the terror group continued, Egyptian media reported. Channel 2's live footage filmed from outside the Gaza Strip intermittently showed isolated billows of smoke streaming out of from apparent explosions in Gaza.Since the start of the IDF ground incursion, the army has struck 260 terrorist targets, 140 of which have been hit since Friday morning.The IDF said it killed over 40 terrorists and arrested 21 others since the ground incursion started. The military said that Palestinians fired mortars at troops in the southern Gaza Strip. In response, IAF aircraft struck at the source of the shooting.