Abdelhamid Abaaoud, the Belgian militant suspected of orchestrating the Paris terrorist attacks, was killed in a police raid in the northern Paris suburb of St.-Denis early Wednesday, the French authorities announced on Thursday.

The Washington Post reports that confirmation of Mr. Abaaoud’s death followed forensic tests, the Paris prosecutor, François Molins, said in a statement.

The death of the plot’s alleged ringleader ended one chapter of the intense criminal investigation that began on Friday night, when three teams of terrorists, in a series of closely coordinated raids, killed 129 people.

But many questions remained unanswered: how Mr. Abbaoud planned and organized the attacks; whether the Islamic State is planning additional assaults outside its stronghold in Syria and Iraq; and the identities of at least two other attackers.

Also on Thursday, the Belgian police conducted their own sweep in Brussels in relation to Bilal Hadfi, one of the dead Paris attackers. A spokesman for the Belgian federal prosecutor said that the houses of Mr. Hadfi’s friends and relatives were being searched. One person has been detained for questioning.

Abdelhamid Abaaoud, a 27-year-old Belgian, was killed in a Wednesday raid in the Paris suburb of St.-Denis. He is believed to have orchestrated Friday’s attacks in Paris. By YOUSUR AL-HLOU on Publish Date November 19, 2015. Photo by via Reuters. Watch in Times Video »

The latest search for suspects came as the French prime minister, Manuel Valls, said an attack using “chemical or biological weapons” in France could not be ruled out, and the Belgian prime minister, Charles Michel, asked Parliament to approve a variety of strict new security measures.

Separately, the White House said President Obama would not abandon plans to attend climate change talks in Paris at the end of the month despite security concerns in the city. The Paris prefecture has extended a ban on protests in the Paris area until Sunday.

At least some of the Belgian raids were being conducted in Molenbeek, the Brussels district that has emerged as a crucial link in the investigation of the attacks.

Molenbeek was the base for Mr. Abaaoud, the Belgian who is believed to have organized the attacks, and two Abdeslam brothers: Salah, who is still at large, and Ibrahim, who died after he detonated a suicide bomb at a cafe on Friday.

Mr. Abaaoud was the focus of a raid on Wednesday in St.-Denis, a suburb on the northern edge of Paris, that ended with eight people in custody.

Mr. Valls, in a speech at the French National Assembly, where lawmakers were debating a three-month extension of a state of emergency, warned that “we must not rule anything out” when considering the possibility that terrorists might use chemical weapons, although he did not provide any evidence to suggest that such an attack was in the works.

Mr. Valls also called for reinforced tracking of movements of people within the European Union and urged European countries to improve the sharing of airline passenger information.

“France has been attacked,” Mr. Valls said in justifying the need to extend the state of emergency. “French people are under shock. They are expecting from all of us some strong, quick and effective reactions.”

Among some long-term measures, Mr. Valls announced the creation of a “structure for radicalized youths” that would accommodate those who say they have abandoned extremist views. Admission to the program would be contingent on a judicial review, Mr. Valls said, and jihadists returning from Iraq or Syria would not be allowed.

On Wednesday, President François Hollande announced at a gathering of French mayors that local police forces that requested them would be provided with weapons and bulletproof jackets, taken from the stocks of the national police.

The National Assembly, France’s lower house of Parliament, later approved a three-month extension of the state of emergency that Mr. Hollande declared after the attacks. The three-month period would begin on Nov. 26th; France’s upper house of Parliament, the Senate, will consider the extension and vote on Friday.

In Belgium, Mr. Michel announced new security measures intended to strengthen the fight again terrorism, and called for closer international cooperation to combat terrorism and the Islamic State by strengthening Europe’s external borders and by working together at the United Nations.

He asked Parliament to double the budget for state security in fighting terrorism, adding 400 million euros, or about $427 million, and to extend the maximum detention time without charges in suspected terrorism cases to 72 hours from 24 hours. He also called on lawmakers to give the government the authority to shut down mosques that preach hate speech.

The government also said it would increase recruitment for security forces, and would invest in new technology and better communication systems. It will also extend the use of investigative methods for terrorism cases, like wiretapping and raids on private homes, to other crimes, in particular arms trafficking, a new priority.

If Parliament passes the measures, Belgians who travel abroad to fight with the Islamic State would be imprisoned upon their return, and people believed to be at risk of going overseas to wage jihad would be given an electronic bracelet and could be stripped of their Belgian citizenship, a measure that France is also considering.

Other Belgian measures would shut down websites that propagate hate speech and would introduce routine identity controls for passengers boarding planes and high-speed trains. Also, for the first time, the authorities would be allowed to conduct raids on at night in terrorism cases; currently, raids are not allowed between 9 p.m. and 5 a.m.

The measures follow a package proposed in January, one day after a raid in Verviers, Belgium, that killed two men suspected of belonging to a terrorist cell run by Mr. Abaaoud.

In Manila, Benjamin J. Rhodes, the deputy national security adviser, said Mr. Obama would attend the beginning of the climate conference, on Nov. 30 and Dec. 1, along with many other world leaders.

“We are planning for him to go to Paris,” Mr. Rhodes said. “We have great confidence in our French partners.”

Mr. Rhodes said the United States had been coordinating with the French authorities on intelligence since the Paris attacks, though he said the French would make the ultimate decisions on security for world leaders at the climate talks.