A convicted murderer has been put to death in the United States after dropping his appeals against the sentence.

Rigoberto Sanchez-Velasco, a Cuban immigrant, was given a lethal injection at a Florida prison on Wednesday after state-appointed psychiatrists ruled that he was competent to make the decision over his death.

Sanchez-Velasco: "I have killed people repeatedly"

Sanchez-Velasco had been convicted originally of murdering an 11-year-old girl and went on to murder two fellow inmates on death row.

However, opponents of the death penalty have criticised the practice of allowing condemned prisoners to drop their appeals, saying this is tantamount to state-assisted suicide.

Sanchez-Velasco, 43, was declared competent to make the decision on Tuesday after he was examined by three psychiatrists.

Death row

Sanchez-Velasco is the 52nd person executed in Florida since executions resumed in 1976 Florida has executed 246 inmates since 1924

"I love you, everybody," he said after he was strapped to the execution table.

Correspondents say his mouth trembled slightly before the eight-minute execution began at 09:31 local time.

Having come to the US in 1980 along with thousands of other Cubans in the Mariel boatlift, he murdered the daughter of his girl-friend and was sentenced to death in 1988.

While awaiting sentence, he stabbed to death two fellow inmates, Edward B "Mike" Kaprat III and Charles Street in 1995 for which he received two 15-year sentences.

In a letter to the Florida Supreme Court, the condemned man defended his wish to die by writing:

"I have killed people repeatedly, repeatedly, repeatedly, even while being on death row."

Serial killer waits

Dianne Abshire, a member of the Florida Support Group for death row inmates, attacked the authorities for allowing Sanchez-Velasco to be executed, arguing that he had been insane.

Wuornos's life has inspired books, films and an opera

Ms Abshire said another notorious inmate on death row, serial killer Aileen Wuornos, also applied to drop her appeals this week but had her request rejected by President George W Bush.

A Fort Lauderdale attorney reported that Wuornos was not competent to make a decision.

Her execution, scheduled for 9 October, has now been stayed temporarily.

Wuornos, 46, has been convicted of shooting dead six middle-aged men along Florida roads in 1989 and 1990 while working as a prostitute.