There are fears the violence in the Middle East could be spreading into other countries after rockets were launched from Lebanon into Israel.
Israelis and Palestinians have been fighting in Gaza for almost two weeks over who has the right to live where.
But now at least three rockets have been fired from Lebanon, north of Israel, prompting Israeli troops to respond with their own attack.
It comes as officials are pushing for a peace plan in the Middle East.
At least three rockets were fired into northern Israel after another night of heavy attacks by Israel on the Gaza Strip.
Armed group Hamas controls Gaza and has been behind the attacks from there, but it's not clear who's firing the rockets from Lebanon and so far no-one's claiming responsibility for them.
Israeli officials have closed schools in the north and told people living there to stay indoors.
Meanwhile, a senior Israeli official is due to go to Cairo, in Egypt, on Thursday to hear details of a ceasefire plan that's been created by Egypt and France.
It's hoped representatives from Hamas will also go along, although they're not expected to have face-to-face talks with the Israeli officials.
Meanwhile, Israel is pausing its military attacks on Gaza for three hours a day so people in Gaza get food and medicine and visit relatives in hospital.