Hamas militants launched a series of rockets into Israel on Sunday, with around a dozen fired from the flashpoint city of Rafah.

intercepted most of the rockets, with sirens wailing in Tel Aviv and other major cities. The strike comes as Israeli forces have stepped up operations in and around Rafah, which Israel says is the last major Hamas stronghold in Gaza.

Hamas claimed responsibility for the barrage, saying it was in response to “Zionist massacres against civilians.”

Israel has faced mounting international pressure to halt its operations in Rafah, home to around 1.5 million displaced Gazans. Israel has urged civilians in the area to leave zones where it is carrying out military operations against Hamas in a bid to minimize civilian casualties.

Rafah lies on the border with Egypt and has been a vital conduit for humanitarian aid. However, Israel took control of the Gazan side of the crossing this week, prompting Egypt to refuse to allow aid to pass through.

Egypt is refusing to reopen its side of the Rafah crossing until the Palestinian Authority regains control of the Gaza side. It agreed to temporarily reroute aid via Israel’s Kerem Shalom crossing, Gaza’s main cargo terminal, following a call between President Biden and Egyptian President Abdel-Fattah el-Sissi.

entered Gaza via Israel’s Kerem Shalom crossing over the weekend, but UN workers say they have struggled to access the aid due to heavy fighting in the area.

The new aid arrangement comes as a “floating pier” built off the coast of Gaza by the U.S. was damaged over the weekend. The pier is still largely operational, but four vessels that helped to stabilize it broke away due to rough seas.

The U.S. spent around $320 million building the pier, which has been used to deliver aid from the U.S. and other countries. While the pier has been used to transfer some 569 metric tons of aid into Gaza, none of it had reached Palestinians as of last week, the Pentagon said.

The Associated Press contributed to this report