Israel rocket damage
A view of the 'devastating' rocket attack on Israel
The Israeli army hit targets in the Gaza Strip Thursday overnight, hours after a rocket fired from Gaza hit a building in the southern Israeli city of Sderot.

The military said in a statement that "several terror targets" were hit, including a military compund used by Hamas' naval force. Earlier reports in Palestinian media indicated the strikes occurred along the Gaza City beach and in the southern city of Khan Yunis. No casualties were reported.

In light of the rising tensions, UN Special Envoy Nickolay Mladenov arrived in Gaza through the Erez crossing Friday morning, according to reports from the southern Strip.

Thursday's rocket fire comes less than 24 hours after a fire exchange between Israel and Gaza that began when a rocket was fired at Israel from the coastal enclave on Wednesday night.

The rocket that was launched Thursday hit a building that was part of a religious school, but no injuries were reported.

Earlier, rocket sirens blared both in Sderot and in the Gaza-border community of Sha'ar HeNegev.

Gad Yarkoni, the head of Eshkol Regional Council, a community close to the border with the Strip, said following the rocket fire that "for a year and a half we've been in a ridiculous, set ritual. They fire incendiary balloons that cause fires, the Israeli army slaps sanctions, they respond with fire and we find ourselves again in a violent round of escalation for 48 hours. 11 rounds like this thus far have ended with no result... this system isn't working and we expect a drastic change in our reality."

Also Thursday, the Israeli military said it had struck Hamas targets in the Strip and destroyed a terror tunnel in response to Wednesday night's rocket fire.

On Wednesday, the army announced a maritime blockade on Gaza "until further notice" over the continued launching of incendiary balloons into Israel.

The rocket fired overnight Wednesday was the first to be launched at Israel since a cease-fire agreement was reached with groups in Gaza in early May.

At the time, nearly 700 rockets were launched from Gaza into Israel while Israel carried out airstrikes on the Gaza Strip. It was the largest outbreak of violence since the 2014 Gaza war, resulting in four Israelis and 25 Palestinians killed.

Last week, Gaza officials warned of escalation over Israel's "foot-dragging" in implementing the cease-fire agreement. A senior official told Haaretz that Palestinian factions, including Hamas, are demanding the transfer of additional funds from Qatar, a further easing on the import of dual-purpose goods from Israel, and progress on humanitarian projects.