Cambodia's Prime Minister has warned Western nations not to interfere in his country's internal affairs, ahead of its upcoming general election in July.

Hun Sen spoke in the capital Phnom Penh on Tuesday. His remarks came amid growing international concern over the election, after the country's major opposition party was disqualified from taking part.

"Cambodia is an independent and sovereign country," Hun Sen said. Addressing Western nations, he added, "I would like you all to understand that from now until the election, please be silent."

Cambodia's election committee rejected the Candlelight Party's registration earlier this month, claiming the opposition party did not submit necessary documents.

This was not the first time the opposition has been excluded from elections. Candlelight, which came in second in last year's local races, was established after courts forced the Cambodia National Rescue Party to disband in 2018.

The European Union's diplomatic service released a statement after Candlelight's registration was rejected. It called the development a "worrying sign," and said the EU strongly objects to the decision.

A statement from a US Embassy spokesperson in Cambodia cited "threats and incidents of harassment" against media and the opposition, which it said impede the Cambodian people's participation in democracy.

Prime Minister Hun Sen has been in power for nearly four decades. Cambodia holds general elections every five years. At its previous vote in 2018, the ruling party claimed all 125 seats.