GAZA: Israel has carried out further airstrikes and shootings in Gaza, raising concerns over the sustainability of the fragile US-brokered ceasefire with Hamas.

The Palestinian Civil Defence reported that four people were killed in two separate incidents in the al-Shaaf area, east of the Tuffah neighborhood in Gaza City, “by Israeli gunfire as they were returning to check on their homes.”

The Israeli military said it targeted militants who crossed the so-called “yellow line,” approaching Israeli troops in Shujayea, adjacent to Tuffah, and “posed a threat.”

The yellow line, defined in a map shared by US President Donald Trump on October 4, marks the boundary behind which Israeli troops pulled back under the ceasefire agreement.

Residents of Gaza City have expressed confusion about the line’s location due to the lack of visible demarcation. Samir, 50, a Tuffah resident, said, “The whole area is in ruins. We saw the maps but we can’t tell where those lines are.”

Since the ceasefire took effect on October 10, outbreaks of violence have continued, with at least 97 Palestinians reported killed, according to local officials.

Israeli airstrikes on Sunday killed 42 people, including children. Israel claimed the strikes were retaliatory, following a truce violation by Hamas fighters who allegedly killed two Israeli soldiers in Rafah.

Hamas denied any involvement, saying it has no control over its remaining units in Israeli-controlled parts of Rafah and accused Israel of fabricating “pretexts” to resume hostilities.

Hamas, which has released 20 living Israeli captives, said it is facing challenges in completing the handover of the remaining bodies due to “extensive destruction” in Gaza.

The Red Cross received the 13th deceased captive on Monday and transferred the body to the Israeli military, according to the office of Prime Minister Benjamin Netanyahu.

Israel had briefly threatened to halt humanitarian aid shipments into Gaza but later said it resumed enforcement of the ceasefire.

UN spokesperson Stephane Dujarric confirmed aid delivery had resumed, though details on quantities were not provided.

Al Jazeera correspondent Tareq Abu Azzoum reported that military checkpoints continue to block several aid trucks carrying humanitarian supplies.

Israeli strikes in eastern Khan Younis on Monday further fueled fears that the ceasefire may collapse.