KUALA LUMPUR (Reuters) - Two women accused of murdering the estranged half-brother of North Korean leader Kim Jong Un with a banned nerve agent pleaded not guilty at the start of a high-profile murder trial in a Malaysian court on Monday. Indonesian Siti Aisyah, 25, and Doan Thi Huong, 28, a Vietnamese, are charged with killing Kim Jong Nam by smearing his face with VX, a chemical poison banned by the United Nations, at Kuala Lumpur airport on Feb. 13. Both women wore bullet-proof vests as they were led into the court on the outskirts of the Malaysian capital. They face the death penalty if convicted. Police have also named four North Koreans as suspects in the case and an Interpol red notice, an international alert just short of an arrest warrant, has been issued for the North Koreans, who remain at large. Defence lawyers demanded that the prosecution immediately name the four other suspects, who have also been charged, so they can prepare their case.  The charge must be clear,  said Siti Aisyah s lawyer, Gooi Soon Seng. Judge Azmi Ariffin dismissed their request. The two women nodded their heads when the charges were read out by two interpreters. They pleaded not guilty. The prosecution said the women s actions showed  intent to kill the victim  by smearing his face and eyes with VX nerve agent, which a Malaysian post-mortem confirmed had killed Kim. The women told their lawyers they did not know they were participating in a deadly attack and believed they were carrying out a prank for a reality TV show.  The prank practice carried out by the first and second accused with the supervision of the four who are still at large was preparation to see through their common intention to kill the victim,  lead prosecutor Muhamad Iskandar Ahmad said in his opening statement. The two women sat quietly in the packed courtroom. Siti was dressed in a black floral suit, while Huong wore a white long-sleeved t-shirt and jeans.  Juliana Idris, who works at the airport, told the court a man later identified as Kim Jong Nam approached her and asked her to take him to a police station.  She said the man, who spoke English, told her he had been  attacked by a woman from behind ... another one closed his eyes .  His hands were shaking a bit, I don t know why,  she said. Police Lance Corporal Mohd Zulkarnain Sanudin, who was on duty at the airport, said Juliana had brought Kim Jong Nam to him. He said Kim told him a substance had been wiped on his face. Kim s eyes were red and he could see some liquid on his face, Zulkarnain said. He also said the he had wrongly recorded Kim Jong Nam s nationality as South Korean.  The police report I made showed the nationality as South Korean, while on the passport, it was written DPR Korea, whereby I did not know what DPR meant. I was only sure that Korea was South Korea,  he told the court. DPRK are the initials for North Korea s official name, the Democratic Republic of North Korea. Other witnesses described how Kim Jong Nam had seizures at the clinic - his eyes rolled upwards and there was drooling of saliva and mucus. Rabiatul Adawiyah Mohd Sofi, a medical assistant, said Kim Jong Nam was at the clinic for just over an hour and moved to a hospital. By the time they arrived at the hospital emergency ward, they could not get a blood pressure reading, she said.  There was a high probability that there was either a problem with our monitor or the patient had died,  said Rabiatul. The case continues on Tuesday.  