The Islamist group Hamas accused rivals with the Palestinian Authority of sending security officers into northern Gaza under cover of securing aid trucks, the Gaza Hamas-run interior ministry said.
A Palestinian Authority official denied the Hamas accusations.
A senior Hamas interior ministry official told the group's Al-Aqsa TV, that the force's mission was supervised by Majed Faraj, the Palestinian Authority's chief of intelligence.
It said six members of the force, who escorted aid trucks coming through the Rafah crossing with Egypt, were arrested and police forces were in pursuit to round up all other members.
"The suspicious security force that entered yesterday with Egyptian Crescent trucks coordinated its operations entirely with the (Israeli) occupation forces,” the Hamas official said, without providing evidence. The Red Crescent is the Islamic equivalent of the Red Cross.
"The statement by the so-called Hamas interior ministry over the aid entry into Gaza Strip is incorrect," a Palestinian Authority official in Ramallah, in the Israeli-occupied West Bank, said in a statement.
The official, referring to the Israel-Hamas conflict, said the authority wasn't interested in an exchange of media comments that would divert attention from "the suffering of our people in Gaza Strip, and the killing, starvation, and displacement they are living through."
The statement posted by Hamas' Al-Aqsa TV on its Telegram accounts said police officers and fighters of militant factions were instructed to treat any forces that entered Gaza without coordination with them as an "occupation force."
Hamas seized control in Gaza in 2007, a year after sweeping elections, following a brief civil war with Palestinian Authority (PA) security forces, reducing the PA's rule to the Israeli-occupied West Bank. Efforts to reconcile the two sides have so far failed over thorny power-sharing issues.
Hamas leaders vowed any attempt to exclude the group from Gaza rule after the war ended was "delusional."
Reporting by Nidal al-Mughrabi in Cairo and Ali Sawafta in Ramallah