TWO LOCATION FRENCH HOSTAGE CRISES: Kouachi Brothers, Charlie Hebdo Suspects Killed; Kosher Supermarket Gunman Killed; Four Hostages Reportedly Killed

Smoke is seen at left as French police special forces launch their assault at a kosher supermarket (seen at rear) where several people were taken hostage near the Porte de Vincennes in eastern Paris January 9, 2015.(Reuters / Gonzalo Fuentes)

Four people and one hostage-taker have been killed at a supermarket in Paris as security forces undertook a rescue operation, according to reports. A worker in Dammartin-en-Goele has been freed, and the two suspects in the Charlie Hebdo massacre killed.

Reuters/Euronews/AFP report several loud blasts were heard and smoke has been rising over the printworks in the industrial zone north east of Paris.

Security forces had the building surrounded for most of Friday before the explosions happened. 

Police take up a position on a roof in Dammartin-en-Goele, north-east of Paris, where two brothers suspected of slaughtering 12 people in an Islamist attack on French satirical newspaper Charlie Hebdo held one person hostage as police cornered the gunmen, on January 9, 2015.(AFP Photo / Dominique Faget)

The National Gendarmerie Intervention Group (GIGN), a special operations unit of the French Armed Forces, launched the assault, reported Le Figaro.

The Hebdo suspects emerged firing on security forces, reported an AFP source. One policeman was reportedly injured in the operation. However, he is not in a critical condition.

Meanwhile, the hostages who were held at the grocery store in Porte de Vincennes in Paris are being released. The hostage taker is reportedly dead, after special forces entered the building and killed him, according to Le Monde.

Subsequent unconfirmed reports suggested that as many of four of the hostages in the kosher supermarket had been killed.

A police union source told Reuters that at least four were feared dead, and that he believed up to 20 hostages in total had been held in the building.

While figures remain unclear, a security source also told AFP that as many as four had been critically wounded.