As tension mounts in Nepal over the massacre of the royal family, authorities have arrested the editor and two executives of a newspaper for suspected treason.

The arrests are thought to be linked to an article published in the Kantipur Daily written by a top Maoist rebel leader criticising the new monarch, the dead King Birendra's brother, Gyanendra.

The curfew was imposed after three people died in rioting

Authorities imposed a curfew in the capital, Kathmandu, for the third night running on Wednesday amid continued tensions among Nepalis sensing a government cover-up over the killings.

The article called on the army to rise up against the new king and accused him of being part of a conspiracy to kill his brother, and most of the Nepalese royal family.

Kantipur editor Yubaraj Ghimire, managing director Kailash Shiroiya and director Binod Gyawali were taken into custody at the newspaper's offices, witnesses said.

Expectations that a government-appointed commission into the deaths would report by the end of the week were dealt a blow when the chairman said work would not start until Friday.

The commission has been delayed by the refusal of the head of the United Marxist Leninist Party, Kumar Nepal, to join it, despite an appeal by King Gyanendra.

Protesters shot

Mr Nepal said he wanted other parties to be associated with the inquiry.

Crown Prince Dipendra was reported to be a heavy drinker who was fond of guns

His party also says the committee had been set up unconstitutionally, because the proposal came from the king, rather than the prime minister.

King Gyanendra has called Friday's fatal shooting an "accident" - to the disbelief of many angry Nepalis.

Three protesters were shot and killed on Monday night and police said they shot and wounded 14 people and arrested 460 on Tuesday night for violating the curfew.

The massacre at the royal palace on 1 June left King Birendra and seven of his immediate family dead.

First reports said the gunman had been the late king's son, the then Crown Prince Dipendra, who was briefly monarch as he lay in a coma with severe bullet wounds. He died on Monday.

The late Dipendra's uncle said on Wednesday that his nephew had been drinking and was thrown out of a royal gathering by King Birendra, before he returned with an assault rifle and gunned down his parents and seven other relatives.

Suraj Shamsher Rana, who spoke to survivors, said Prince Dipendra had shot himself after opening fire on his family.

Rebellion fears

"Yes, indeed, there is no question about that. The crown prince killed the others and then shot himself," he told the Associated Press news agency in an interview. He declined to speculate about Prince Diprendra's motives.

First reports that the crown prince had been responsible for the massacre were subsequently denied, with an official statement speaking only of an accident in which there was a sudden discharge of a weapon inside the royal palace.

Hundreds of tourists have been stranded

King Gyanendra has admitted that the second explanation - which was issued when Dipendra was alive, though critically wounded in hospital - may have been influenced by "legal and constitutional hurdles".

While alive, Dipendra was king and it would have been impossible under the constitution and by tradition to accuse him of mass murder.

Some observers say that unless the truth about the royal massacre comes out, there could be a rebellion against the monarchy.

The violence has left hundreds of tourists stranded in Nepal as they scrambled for flights to take them out of the country.

But with many flights cancelled, many were forced to stay inside hotels and guest houses and watch the proceedings on television.

Several countries, including the United States, Britain and Thailand, have advised their citizens to avoid travel to Nepal.