Police in France have swarmed an area northeast of Paris where the suspects in a deadly newspaper attack are believed to be located and holding at least one hostage.
Live TV reports say police have cornered the suspects in the town of Dammartin-en-Goele and are currently holding negotiations.
An Interior Ministry spokesman says there is "near certainty" that the suspects -- brothers Cherif and Said Kouachi -- are in an industrial building surrounded by police.
AP reports that authorities have closed two runways at Charles de Gaulle international airport, which is located near the site of the standoff.
Air France said two of its planes were forced to abort initial landings and approach the airport again due to helicopters "flying over the zone at low-altitude."
Schools in the area have gone into lockdown and residents have been asked to stay in their homes with the lights off.
French Interior Minister Bernard Cazeneuve says an operation is under way to "neutralize" the suspects.
The development comes after police reportedly engaged in a car chase with the Kouachi brothers, in which shots were fired.
Early reports of casualties on January 9 have since been denied.
The suspects are believed to have taken at least one hostage, reportedly a woman.
They are suspected of killing 12 people during the January 7 assault on the office of satirical newspaper Charlie Hebdo in Paris, the deadliest attak in France in half a century.
The paper had been threatened by the Al-Qaeda militant group for its caricatures of the Muslim Prophet Muhammad.
The victims of the attack included eight journalists and two police officers.
The attackers said they wanted to "avenge the Prophet" during the attack on the magazine, which had drawn repeated threats for its caricatures of the Prophet Muhammad.
Witnesses said the attackers claimed allegiance to Al-Qaeda in Yemen during the assault.
Prime Minister Manuel Valls declared that France was at "war" with terrorism but "not in a war against religion."
"It will without doubt be necessary to take measures" to respond to the terrorist "threat," he said.
President Francois Hollande said France must "try to foster an even stronger prevention against possible repeats of the events we just experienced."
Both Kouachis are on the United States' no-fly list of suspected terrorists.
Reuters cites a senior Yemeni intelligence source as saying Said Kouachi, 34, visited Yemen in 2011 and met the late Al-Qaeda preacher Anwar al Awlaki during his stay.
Cherif Kouachi, 32, was convicted of terrorism charges in 2008 for his links to a network sending jihadis to fight American forces in Iraq.
Speaking January 8 on French TV, Kouachi's former lawyer called on Cherif Kouachi to "hand himself over to police authorities so that all light can be shed on this case."
The Islamic State militant group has praised the deadly attack, calling the gunmen "heroic jihadists."
European Union chief Donald Tusk said on Janary 9 that the EU's next scheduled summit will include discussion of antiterrorist efforts following the Paris attack.
He said he intends to use the February 12 summit "to discuss more broadly the response the EU can bring to these challenges" following the "barbaric attacks in Paris."
The partner of Charlie Hebdo's editor says Stephane Charbonnier, who was among the dead, said he and his colleagues "died defending freedom of expression, secularism."
"They have died so we can stay free in this country," Jeannette Bougrab said on French television station BFMTV on January 8.