CASTRIES, St. Lucia (Reuters) - The prime minister of the small Caribbean country of St. Lucia has asked the immigration ministry to weigh imposing visa requirements on visitors from Venezuela, in a show of protest against an ally that has been its key energy benefactor.

Allen Chastanet said earlier this week that he was “deeply concerned” by the situation in Venezuela, where months of protests against unpopular President Nicolas Maduro have led some regional allies to turn their backs on one of the world’s top petroleum producers.

“I have asked the Ministry of Immigration to look at imposing a visa restriction on Venezuelans coming to St. Lucia,” he said at a press conference on Monday. Currently Venezuelan nationals are free to travel to the island without visas.

St. Lucia joined the Venezuela-backed regional integration ALBA and Petrocaribe organizations in 2013, and has enjoyed a close-knit relationship with Caracas.

St. Lucia’s links with Petrocaribe have provided it with a regular, discounted supply of petroleum products from Venezuela, but it has not received any crude this year, according to Venezuelan state-owned oil company PDVSA’s internal trade reports.

Chastanet also criticized the Maduro government for not respecting the rule of law, adding that the chaotic situation in Venezuela poses a security threat for the region.

Anti-government protests have rocked Venezuela for four months, leaving more than 120 people dead.

However, the protests have fizzled as a controversial Constituent Assembly, which has been criticized globally as a sign that Venezuela is turning into a dictatorship, started working earlier this month.