An Israeli tank brigade has seized control of the Gaza Strip side of the Rafah border crossing with Egypt, authorities say, moving forward with an offensive in the southern city even as cease-fire negotiations with Hamas remain on a knife’s edge.

The move comes after hours of whiplash in the Israel-Hamas war, with the militant group on Monday saying it accepted an Egyptian-Qatari mediated cease-fire proposal. Israel, meanwhile, insisted the deal did not meet its core demands. The high-stakes diplomatic moves and military brinkmanship left a glimmer of hope alive — but only barely — for an accord that could bring at least a pause in the 7-month-old war that has devastated the Gaza Strip.

The Israeli 401st Brigade entered the Rafah crossing early Tuesday morning, the Israeli military said, taking “operational control” of the crucial crossing. It’s the main route for aid entering the besieged enclave and exit for those able to flee into Egypt.