WASHINGTON (AFP) - Russia's proposal to place Syria's chemical weapons under international control would be troublesome to enact given it would require time and total cooperation from a secretive regime fighting for survival.

Experts say the idea floated by Russian Foreign Minister Sergei Lavrov on Monday, in which Syria's arsenal would be destroyed under supervision, ventures into unchartered territory, as previous arms control efforts have been carried out after - and not during - a conflict.

With more than 1,000 tonnes of chemical agents and precursor chemicals, the Syrian regime, suspected of using such weapons, has one of the world's most significant stockpiles, according to a French intelligence report.

But the process of removing such arms from President Bashar al-Assad's reach while rebel fighters continue to push for the fall of his government would present major difficulties even if such an accord was reached.

"It's hard for me to imagine how that would happen in the middle of a civil war," said Daryl Kimball, executive director of the Washington-based Arms Control Association.

"Because this is a very difficult engineering task. It requires facilities to be built to destroy the weapons," Mr Kimball told AFP when asked about the Russian proposal.

Such an undertaking would require a long-term international presence to track the process, said Mr Kimball, adding: "It's not something you want to do with the threat of mortar shells hitting the area."

The Russian proposal implies that Syria would have to sign the international Chemical Weapons Convention, forcing it to divulge every detail of its arsenal - a radical move for a regime preoccupied with buffeting its foes, both foreign and domestic.

Former UN weapons inspector David Kay, who oversaw the search for weapons of mass destruction in Iraq that were never found, has said any effort to secure chemical weapons sites in Syria would require elaborate, round-the-clock security to "ensure that others are not entering."

Even in peaceful settings, destroying a country's chemical stockpile under international law is a complicated undertaking that takes years and billions of dollars, with international inspectors on hand at every step.

Under the international convention, the United States has spent nearly US$35 billion to incinerate 90 percent of its stockpile over more than two decades.

Special destruction chambers had to be built at chemical weapons depots across the country with bombs, rockets and artillery shells destroyed one by one.

The painstaking task may not be completed until 2021, according to arms control expert Paul Walker of the non-profit group Green Cross.

Since the 1990s, Russia also has invested heavily in efforts to eliminate its arsenal. And as of 2012, Moscow had destroyed 54 percent of its chemical weapons, according to the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague.

There are essentially two ways to get rid of chemical weapons: burning them in an incinerator, which has been the primary method in the United States; or neutralizing them with other chemicals, which has been the approach in Russia and - most recently - Libya, experts said.

Neutralising lethal agents drastically reduces their toxicity to a level equivalent to typical industrial waste, according to Michael Luhan, spokesman for the OPCW.

In Libya, one of 189 countries to sign on to the convention, authorities use a "mobile destruction facility" to inject a neutralizing chemical into batches of prohibited agents, he said.

When a government agrees to the convention, it has to identify its stockpile in minute detail, "down to the kilo of agents and type of munitions," Mr Luhan said.

That comprehensive inventory then becomes the baseline for destroying the weapons.

If Mr Assad was to agree, "it would be a 180 turn-around for Syria to acknowledge they have chemical weapons and get rid of them," Mr Kimball said.

Given Syria's track record, there would need to be the threat of force from a UN Security Council resolution to make sure the country made good on its pledges, he said.

"It would be important to maintain the threat of force to ensure that Assad fully declares his chemical weapon stockpiles."