Holding his teddy bear, Gazan mother Asmaa al-Wasifi mourned her 10-year-old son, who was killed in an Israeli strike before he could take his second polio shot. The United Nations began the second round of its polio campaign in central areas of the enclave on Monday,

Strikes by Israel have killed at least 73 people including women and children in Gaza, Hamas run authorities have said. The attacks were on the city of Beit Lahia in northern Gaza with dozens of others buried beneath rubble, according to the reports.

Health workers in Gaza are concerned polio vaccines won’t reach the north of the enclave because of ongoing fighting.