Egyptian security forces have fought gun battles in a town near Cairo after launching an operation targeting "terrorist elements".
The clashes in the town of Kerdasa in Giza have left one senior police officer dead and nine others injured, while at least 65 people have been arrested, according to the Interior Ministry.
A joint police and army operation to take the back from groups loyal to deposed President Mohamed Morsi began at about 5:30am local time (03:30 GMT) on Thursday.
Security troops launched the operation to arrest people accused of torching police stations and killing about 11 security officers in clashes that erupted following the army's overthrow of Morsi in July.
Al Jazeera's special correspondent in Cairo, who is not being named for security reasons, said police went into the area "heavily armoured" in order to "root out and arrest terrorists".
General Nabil Farrag had just given a pep talk to his men on the street, preparing them to roll into Kerdasa, when they came under gunfire, according to an Associated Press video journalist and a photographer working with AP.
Army soldiers and policemen took cover behind armoured vehicles and behind walls.
However, Farrag fell with a bullet wound getting past the body armour he was wearing.
He lay in the street for nearly 15 minutes, blood soaking through his white uniform, until his men could reach him and carry him into a sedan to take to a hospital.
The Interior Ministry, which is in charge of the police, later announced Farrag's death.
According to Egyptian state TV, one of those arrested on Thursday was Ahmad Uways, the man accused of killing the head of Kerdasa police station on August 14.
It said police forces took control of the area and imposed a curfew.
Security forces had not been allowed in Kerdasa since then, but authorities had previously promised to respond to the deadly attack on the police station.
Kerdasa, known for producing and selling fabrics, is 14km from Cairo and known to be an Islamist stronghold.
Residents of the area said on Wednesday they were not in control of the area but do not want any police presence there.
Against this backdrop of domestic unrest, Egypt has returned $2bn that Qatar had deposited with its central bank, after talks to convert the funds into three-year bonds broke down, Hisham Ramez, Egypt's central bank governor, said on Thursday.
Egypt authorities have also rejected a Qatari request to increase the number of flights between the two states, according to Egyptian airport sources, in a further sign of diplomatic tensions.
|Egypt returns $2bn to Qatar in sign of growing tensions
Qatar had been a firm backer of Morsi's Muslim Brotherhood and lent Egypt $7.5bn during the year he was in power.
Morsi's removal in a move orchestrated by the Egyptian military on July 3 led to nationwide protests by his supporters.
Violence between his backers and security forces included massive attacks on police stations, security officers and churches.
At least 1,000 people have died in the violence with most deaths coming during the security forces' dispersal of two pro-Morsi sit-ins in Cairo on August 14.
About 100 police officers also died in the clashes.
The latest raid is part of concerted efforts by the authorities to retake areas that have been off-limit for the police since weeks.
On Monday, security forces stormed the town of Delga in Minya province, about 300km south of Cairo, and arrested 56 residents.
"What is happening today echoes what happened in Delga. There were similar circumstances. It was also off limits for police for weeks," our correspondent said.