Security officials announced on Wednesday that a massive terror attack was averted when explosives were discovered hidden among medical supplies belonging to two sisters on their way to receive cancer treatment in Israel.

The Shin Bet (Israeli internal security) stated that material used to make explosives was discovered hidden in tubes labelled “medical materials” being brought into Israel by two Gazan residents. The sisters had received permits to enter Israel so that one could be treated for cancer. The explosives were found during a routine security check at the Erez Crossing and disposed of by sappers. The Shin Bet revealed that Hamas wanted to smuggle the explosives in order to perpetrate an attack in Israel.

“Unfortunately, this is more proof that terror groups in Gaza are continuing to take advantage of humanitarian channels to export terror into Israel’s heartland,” Defense Ministry Crossing Points Authority head Kamil Abu Rokan said in a statement. “The security checks at the crossing worked exactly as we expect and with notable professionalism.”

Despite treating tens of thousands of Gazans every year for medical issues, Israel is criticized for reluctance in issuing permits to cross the border.