SHENZHEN, China - China executed on Wednesday three Filipinos convicted of drug trafficking despite a flurry of public appeals for clemency in the Philippines, and days after Amnesty International slammed Beijing's sweeping use of the death penalty.

The three, two women and a man, were caught smuggling several kilograms of heroin each into China in 2008. Under Chinese law, the trafficking of at least 50 grammes of any illicit drug is punishable by death. "It is a sad day for us, up to the last minute we were doing everything we can to postpone the execution," Vice President Jejomar Binay said in a radio interview from Qatar.

He said he sent an appeal on Tuesday asking to keep the Filipinos alive while Manila investigated new evidence that could have proved the innocence of at least one or two of the three.

"The sad part is China did not grant our request and proceeded with the execution of the three Filipinos," said Binay, who flew to Beijing in February and gained a brief delay of the death sentences.

Elizabeth Batain, 38, was executed by lethal injection at a prison in the southern Chinese city of Shenzhen. Sally Ordinario-Villanueva, 32, and Ramon Credo, 42, were executed in the port city of Xiamen.

The three were told on Wednesday morning that their sentences would be carried out later in the day, Philippine officials said, and they were allowed visits by family members.

In the Philippines, prayer vigils and Masses were held, while a rally of overseas foreign workers was planned later on Wednesday. Millions of Filipinos work overseas, including thousands employed as maids in Hong Kong.

Serious offense

The three are the first Filipinos to be executed in China for drug trafficking, said Philippines officials.

The families of two of the prisoners had sent open letters appealing for clemency, arguing they had been set up.

"We believe our loved ones are victims of larger drug syndicates who take advantage of the unawareness, vulnerability and desperation of our people," the families wrote. "We are pained that they are meted the death penalty while the big true drug operators and syndicates go on wild abandon."

China's foreign ministry said that drug trafficking was a serious offense and that justice had been served.

"This is an isolated criminal case. I do not want it to affect bilateral relations," said spokeswoman Jiang Yu at a regular briefing on Tuesday.

Despite competing claims over the resource-rich Spratly Islands in the South China Sea and criticism last year over the botched police handling of a hostage crisis in Manila that led to the deaths of Hong Kong tourists, bilateral relations between China and the Philippines have been relatively stable.

The executions come after Amnesty International again slammed China's human rights record and widespread use of the death sentence in its latest annual report on the issue.

China is now believed to execute far more people than the rest of the world combined, even though the nation does not release official statistics.

China has executed several other foreigners for drug offenses, including Japanese, Nigerians and a Briton in 2009.

While China maintains an iron grip on crime with 55 offenses still punishable by death, far more than many other nations, it has scrapped the death penalty for nearly a dozen non-violent crimes including smuggling cultural relics and tax fraud.