PARIS — (CNN) French experts are trying to determine whether an object found in a garbage can in a Paris suburb is a suicide vest like those used by the ISIS jihadists who carried out the recent terrorist attacks on the city.

Security forces sealed off streets Monday in Montrouge, a suburb just to the south of Paris, and a bomb squad headed to the scene after investigators found the possible suicide vest.

Paris police told CNN that it’s not yet clear whether the object contained explosives. CNN affiliate BFMTV reported that the item, which resembled a suicide vest, contained bolts and TATP, the same explosive found in the suicide belts used by Paris attackers.

Could there be a connection between the garbage can discovery and the coordinated series of shootings and bombings that killed 130 people in Paris on November 13?

Officials aren’t making that link so far. But BFMTV and the French newspaper Le Monde reported Monday night that the cell phone of suspect Salah Abdeslam, who’s still at large, was tracked to the Montrouge area soon after the attacks.

“The big question is going to be: Is this the suicide vest that Salah Abdeslam was tasked to use?” CNN terrorism analyst Paul Cruickshank said. Questions have already been raised over whether Abdeslam aborted part of the attacks before fleeing to Belgium.

And there are other questions, too, Cruickshank said. If it is a suicide vest belonging to Abdeslam, why would it have been discovered as late as Monday, 10 days after the attacks? And if it doesn’t belong to him, then whose is it?

“It is possible that somebody else may have jettisoned it, an attacker that we don’t know much about at this point,” Cruickshank said. “So they’ll be doing all sorts of forensics, trying to establish who this belonged to, and that will be a huge priority for French investigators.”

Local authorities in Montrouge said that the garbage cans in the area are emptied “once or twice a week,” Le Monde reported, underscoring the puzzle over how and when the possible suicide vest ended up in one of them.

Abdeslam is thought to be using a support network in Belgium to avoid being captured, more than a week after an international arrest warrant was issued for his arrest in connection with the Paris attacks.

Sources in France close to the ongoing investigation believe Abdeslam could not have survived so long on the run without help. They say that extensive raids in Belgium on Sunday and Monday, in which 21 people were detained in several locations, targeted individuals suspected of a role in the network that organized the attacks.

Seventeen of those arrested have since been released. Authorities charged one man with participating in the activities of a terrorist group in connection with the Paris attacks.

French authorities have said the wave of assaults on their capital was organized in Belgium, with jihadists taking advantage of intelligence gaps and the absence of border controls between the two countries to slip into France undetected.

Several of the men believed to have taken part in the attacks have strong ties to Brussels, notably its suburb of Molenbeek, which has a history of links with terrorism plots.

So far, the operations in Belgium haven’t uncovered Abdeslam, and there’s “unprecedented concern” among Belgian authorities, Cruickshank said.

Brussels, which has been under partial lockdown since Friday night, is to remain at the highest terror alert level until at least the start of next week. Schools and the metro will stay closed until Wednesday at the earliest, Belgian Prime Minister Charles Michel announced Monday.

He has warned of the threat of attacks in Brussels similar to those that hit Paris, with militants using guns and explosives to target multiple locations.

“Belgian police don’t have a handle on where these guys are and that’s why they’re shaking the tree so hard,” Cruickshank said.

The concerns in the aftermath of the atrocities in the French capital stretch well beyond Western Europe. A new U.S. intelligence bulletin warns law enforcement to review training for dealing with active shooters after the Paris attacks showed signs of prior surveillance, tactical planning and military-style training.

Amid the ongoing tensions, French President Francois Hollande is in the midst of a week of whirlwind diplomacy aimed at building a broader global coalition to fight ISIS in its strongholds in Syria and Iraq.

After hosting British Prime Minister David Cameron in Paris on Monday, Hollande will visit Washington to meet with U.S. President Barack Obama on Tuesday, then hold talks with German Chancellor Angela Merkel on Wednesday and travel to Moscow to see Russian President Vladimir Putin on Thursday.

France and Britain are already part of a U.S.-led coalition that’s been bombing ISIS targets. Russia has been conducting its own separate airstrikes against ISIS and other groups in coordination with the forces of Syrian President Bashar al-Assad.

Any efforts to form an alliance that includes both Russia and the United States are likely to run into thorny issues like Assad’s future role in Syria and international sanctions against Moscow for its interference in Ukraine.

Hollande has vowed to intensify the aerial campaign against ISIS targets, and the French military began Monday to use the aircraft carrier Charles de Gaulle in the eastern Mediterranean to launch strikes.

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