The World Health Organization said that its staff residence and main warehouse in Gazan city of Deir Al-Balah was attacked thrice on Monday.
Two WHO staff and two family members were detained, said Tedros Adhanom Ghebreyesus, the WHO Director-General, adding that three were later released, while one staff member remained in detention.
Israeli tanks pushed into southern and eastern districts of the Gazan city of Deir Al-Balah for the first time on Monday, an area where Israeli sources said the military believes hostages may be held.
