It may be possible for the United Nations to disarm Syria of its chemical weapons, but the complex operation probably would require years to complete and would be extraordinarily difficult while much of the country is consumed by civil war.

As the White House and its allies moved closer Tuesday to seeking U.N. support for a Russian proposal to collect and destroy Syrian President Bashar Assad’s vast arsenals of toxic weapons, veteran inspectors and other experts began to focus on the technical and logistic challenges such a plan would entail.

The biggest question is whether Syria would disclose its clandestine procurement systems, development and production infrastructure, chemical supplies, weapons stores, armed delivery systems, command-and-control networks and other details necessary to verify compliance.

“The Syrians would have to tell us basically everything, and they’d also have to confess to using chemical weapons, which they may be reluctant to do” because it could make commanders vulnerable to charges of war crimes, said Markus Binder, a chemical weapons expert at the University of Maryland.