Explosive vest 'contained same materials used in Paris attacks'
Belgian authorities earlier charged a fourth suspect with terrorism offences
An explosive vest found in a suburb south of Paris contained bolts and the same type of explosive used in the November 13 attacks on the French capital, officials have revealed.
The vest - which had no detonator - was found on Monday by a street cleaner in a pile of rubble in Chatillon-Montrouge, just south of Paris.
An official said laboratory analysis showed that the explosive material was TATP - used in seven other explosive vests in the attacks which killed 130 people and wounded hundreds of others.
In addition, the vest was found in the same zone where the mobile phone of a man sought by police was located.
Police have been conducting a manhunt to find Salah Abdeslam, but it is not known if the explosive vest was abandoned by him.
He was stopped by police in northern France after the attack, but allowed to continue his journey to Belgium.
Citing a "serious and imminent" threat of attack, Belgium's prime minister announced that Brussels will remain at the highest alert level for at least another week, maintaining security measures that have severely disrupted normal life in the capital.
Charles Michel said Brussels, which houses the headquarters of the European Union and Nato, faces a "serious and imminent" threat that required keeping the city at the highest alert level, while the rest of the country would stay at the second-highest level.
Belgium's crisis centre said the alert level would only change if a significant breakthrough warranted it.
The increased security measures in the wake of the November 13 massacre in Paris have virtually shut down the Belgian capital, with the subway system, many shops and schools remaining shut on Monday.
Mr Michel said that despite the continued high alert level, schools would reopen on Wednesday, with parts of the subway system beginning to operate the same day. He did not say when the system would be completely online again.
"We are very alert and call for caution," Mr Michel said.
"The potential targets remain the same; shopping centers and shopping streets and public transport.
"We want to return to a normal way of life as quickly as possible," he added.
The unprecedented security measures come as authorities hunt for one or more suspected extremists, including Abdeslam.
Belgian authorities have not announced any details of their investigation into potential attacks nor have they released any information about four suspects who have been arrested and charged with terrorism-related offences.
These include one suspect who was arrested as part of a sweep that saw 21 people detained since Sunday night. Fifteen have since been released.
Seeking a unified strategy on Syria, French president Francois Hollande is due to meet US president Barack Obama and German chancellor Angela Merkel on Wednesday, before travelling to Moscow on Thursday for talks with Russian president Vladimir Putin.
France's defence ministry said it had launched its first air strikes from the Charles de Gaulle aircraft carrier, bombing IS targets in the Iraqi cities of Ramadi and Mosul in a seven-hour operation.
The ministry said four Rafale fighter jets were sent from the carrier on Monday afternoon. France has already carried out strikes against IS targets in Syria.
A series of raids in Belgium began late Sunday, capping a tense weekend that saw hundreds of troops patrolling streets.
Several of the Paris attackers had lived in Brussels, including Abdelhamid Abaaoud, the man who authorities say orchestrated the plot. He was killed on Wednesday in a stand-off with French police.
French authorities issued a new appeal for help in identifying one of the three attackers who was killed in the assault near the national stadium. They posted a photo of the man on Twitter on Sunday asking the public for information.
Last week, France extended for three months a state of emergency that allows police raids, searches and house arrest without permission from a judge. On Saturday, it also extended a ban on demonstrations and other gatherings through until November 30, when a UN climate conference with more than 100 heads of state is scheduled to start.
The Islamic State group has claimed responsibility for the Paris attacks, as well as two other attacks over the past month: suicide bombings in Beirut that killed 43 people, and the downing of a Russian jetliner carrying 224 people in Egypt's Sinai Peninsula.