MANILA - Manila demanded an explanation Thursday after its ambassador to Kuwait was expelled, shocking Philippine authorities and deepening a diplomatic row over the treatment of domestic workers in the Gulf state.

The two nations had been working to resolve differences sparked by the murder of a Philippine maid, whose body was found stuffed in her employer’s freezer in Kuwait earlier this year. But relations plunged after the Philippines released videos last week of embassy staff helping Filipino workers flee from allegedly abusive employers, which Kuwait called a violation of its sovereignty.

Philippine Foreign Secretary Alan Peter Cayetano apologised, but Kuwaiti officials announced Wednesday they were expelling ambassador Renato Villa and. “The department served a diplomatic note to the Embassy of Kuwait conveying its strong surprise and great displeasure over the declaration of Ambassador Renato Pedro Villa as persona non grata,” the ministry said in a statement.

In the note, Cayetano also demanded the Kuwaiti government explain “the continued detention of four Filipinos hired by the Philippine embassy and the issuance of arrest warrants against three diplomatic personnel”.

Manila has said its embassy hired three of the detained Filipinos for the rescues.

Speaking to reporters in Singapore, Cayetano said he disapproved of the release of the videos but defended the action of the embassy staff, citing urgency.

“We’re still optimistic, we’re hoping for the best but also preparing for the worst,” he said late Thursday, adding there are around 262,000 Filipinos in Kuwait, nearly 60 percent of them domestic workers.

Philippine President Rodrigo Duterte’s spokesman Harry Roque said he hoped bilateral ties would not worsen further.

Tensions rose earlier this year following the murder of maid Joanna Demafelis, prompting Duterte to ban Filipina workers from deploying to Kuwait for work.

Duterte had alleged that Arab employers routinely rape their Filipina workers, force them to work 21 hours a day and feed them scraps.

Relations appeared to recover after a Kuwaiti court sentenced to death in absentia a Lebanese man and his Syrian wife for Demafelis’ killing.

Following the verdict, Duterte this month announced plans to visit Kuwait to seal an agreement on workplace safety guarantees for the 252,000 Filipinos working in the Gulf nation. But Cayetano on Thursday expressed doubt about the deal because “the ambassador (of Kuwait)... was suddenly recalled and is not answering our inquiries at this point in time”.

The proposal sets terms for vacation leaves, food and custody of passports, Duterte’s spokesman Roque said. Some 10 million Filipinos work abroad and the money they send home is critical to the Philippine economy.