26 March 2014 Last updated at 19:42 ET

Judge rejects 'secret' Oklahoma capital punishment law

A judge in the US state of Oklahoma has ruled its execution law improperly prevents death row inmates learning the source of the drugs used to kill them.

The finding potentially delays at least two executions and could influence court challenges in other states.

It comes as US states are having increasing trouble obtaining drugs used in executions, amid an embargo from European pharmaceutical firms.

Critics say the states risk botching executions with impure drugs.

In January, an execution in Ohio took 25 minutes to complete, as the inmate reportedly gasped and made choking noises in the moments before he was pronounced dead.

The state used two untried drugs to kill convicted murderer and rapist Dennis McGuire after the maker of the previous execution drug refused to allow its use.

The challenge to Oklahoma's law was brought by convicted murderers Clayton Lockett and Charles Warner, who sought to learn the source of the drugs to be used in their executions scheduled for 22 April and 29 April, respectively.

But Oklahoma state law blocks officials from revealing - even during court proceedings - the identities of the companies supplying the drugs used to sedate the inmates, paralyse their respiratory systems, and stop their hearts.

Executions in decline

On Wednesday, Oklahoma County district court Judge Patricia Parrish ruled the secrecy provision unconstitutional, though her ruling did not affect Lockett's and Warner's death sentences.

"I think that the secrecy statute is a violation of due process because access to the courts has been denied," Ms Parrish ruled, according to local media reports.

It's getting harder for US states to source the drugs used in lethal injections because many European companies don't want their drugs used for this purpose, the BBC's Beth McLeod in Washington reports.

State governments have turned to other suppliers, but lawyers for death row inmates argue that these less regulated drugs can lack purity and cause unnecessary suffering, our correspondent reports.

Capital punishment experts say the Oklahoma decision could affect the several other states where corrections officials are barred by law from disclosing the source of the drugs.

Thirty-two US states have death penalty laws and 18, plus the District of Columbia, have abolished capital punishment.

But in recent years only a handful of states have actually carried out executions - nine in 2013 and seven in 2012.

The annual number of executions has fallen dramatically, from a high of 98 in 1999 to 39 last year.