Reuters reports that a government source cited the protests as the chief cause for the delay. The government plans to sign the memorandum in November 2020.

Argentina first sought to sign the preliminary agreement in August, which aims to double the South American country's pork output - currently 630,000 tonnes per year - in four years.

The announced intention by Argentina to sign the deal, designed to spur exports to meat-hungry China, drew criticism from Argentine environmentalists concerned about the impact that such a rapid increase in pork production would have.

"Given the complaints, we decided to take time to amend the memorandum of understanding, which in a way is redundant because when you invest in Argentina you have to abide by local laws," a source at the foreign ministry told Reuters, asking not to be named because the reason for delay had not yet been made public.

The current draft of the memorandum, with stricter environmental guidelines, is being sent to China for review, the source said.

On Monday 31 August, hundreds of people marched to the historic Plaza de Mayo, next to the Casa Rosada presidential palace in Buenos Aires, in protest against the signing of the memorandum.

On social media, environmental activists invited people to the march, saying: "We are against animal exploitation and repudiate the agreement on industrial pig farms." A letter signed by academics against the deal said it would be "impoverishing, cruel and polluting."

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