May 29 (UPI) -- Israel's military launched airstrikes into Gaza Tuesday to retaliate for a large mortar attack against Israeli settlements, officials said.
The strikes came shortly after Israeli Prime Minister Benjamin Netanyahu vowed to "respond with great force" to the attacks, which officials said included 28 mortar shells.
Israel's military said the mortar shells, which triggered three rounds of sirens in the Sha'ar Hanegev and Eshkol regions, were mostly intercepted by the Iron Dome anti-missile defense system. Some of the mortars, it added, landed on the grounds of a kindergarten before students arrived.
Tuesday's was the largest and most serious exchange of fire in the conflict since 2014.
Hamas said the opposition in the Gaza Strip "reserves its right to react or remain silent in accordance with the interest of our people."
Later on Tuesday, Israeli naval forces said they intercepted a Palestinian vessel hours after it sailed off the coast of the Gaza Strip in protest against Israel.
The boat, carrying 17 patients, students and people injured in recent mass protests, was transferred to the Israeli port of Ashdod. The Palestinians were attempting to break an Israeli-imposed siege with the intention of reaching Limassol, a coastal city in southern Cyprus, Israeli officials said.
Tuesday's events followed days of violence in Gaza.
Monday, Israeli troops killed a Palestinian it said approached Gaza's border with Israel, and Israeli tank fire killed three people in a Palestinian military observation post on Sunday.