The Israeli military said on Monday it had begun carrying out strikes on Hamas targets in the Gaza Strip, hours after a Palestinian rocket hit a house near Tel Aviv.
Reuters witnesses heard explosions in Gaza.
The military said in a statement that it had "begun striking Hamas terror targets throughout the Gaza Strip."
One position hit was a Hamas naval position west of Gaza City, while another was a large Hamas training camp in northern Gaza, Palestinian security officials and Hamas media outlets said.
Both positions were likely to have been evacuated, as Hamas had hours of notice that Israeli strikes were coming.
Witnesses said three missiles hit the northern target.
Israeli Prime Minister Benjamin Netanyahu had promised a strong response to the rocket attack earlier in the day that injured seven Israelis.