Lebanese security officials say the Israeli army has fired eight shells at southern Lebanon after rockets were fired into northern Israel.

This is the second such cross-border exchange since Israel launched an offensive in Gaza on its southern flank on Dec. 27, and it threatens to ignite a second front in the north.

The area has been largely quiet since the 2006 Lebanon-Hezbollah war.

The Lebanese officials say several rockets were fired Wednesday and at least one fell short inside Lebanon. Israeli police say the militants' rockets caused no injuries or damage, but residents were told to head to bomb shelters.

The Lebanese officials spoke on condition of anonymity because they were not allowed to speak to the press.

JERUSALEM (AP) _ Police say three rockets fired from Lebanon have landed in northern Israel.

Police say the rockets landed in open areas near the town of Kiryat Shemona on Wednesday and there were no reports of damage or injuries. People in northern Israel were asked to head to bomb shelters.

Israeli officials have expressed concern that militants in Lebanon could try to open a second front in solidarity with Gaza's Hamas rulers against Israel's 19-day offensive against the militant group.

Four rockets were fired on northern Israel last Thursday. Lebanon's Hezbollah guerrilla group denied responsibility and speculation focused on small Palestinian groups in Lebanon.