52-year-old Kimberly McCarthy was executed by lethal injection at 6:37 pm GMT (23:37 local time) on Wednesday in the prison of the small town of Huntsville after 14 years on death row.

She was the first woman executed in the US in nearly three years.

McCarthy had been sentenced for the robbery, beating and fatal stabbing of 71-year-old retired college psychology professor Dorothy Booth in 1997.

McCarthy had received two last-minute reprieves in January and April due to allegations of racial discrimination. Her victim and all members of her jury were white, while McCathy herself was black.

But after a Texas appeals court refused to reopen the case, she ran out of options.

Outside the prison, about 40 protesters held up signs reading "Death Penalty: Racist and Anti-Poor," ''Stop All Executions Now."

More than 1,300 people have been executed across the United States since the Supreme Court lifted a moratorium on the application of the death penalty in 1976.

Over a third of the executions have been carried out in Texas.

Opinion polls consistently show that between 60 and 65 percent of Americans support capital punishment.

However, juries have become increasingly less willing to impose the death penalty, with only 78 death sentences last year, down by around three-quarters since the 1990s. The number of executions is also declining: 43 people were executed in 2012 down from a peak of 71 in 2002.

32 of the 50 US states still have the death penalty.

According to the Death Penalty Information Center, an academic watchdog in Washington, there are currently 3,125 convicts on death row in the US and McCarthy was the 17th prisoner put to death in the first six months of 2013.

rg/hc (AP, dpa, Reuters)