A U.N. envoy said Monday a peaceful solution to election impasse in Bangladesh was possible despite boycotts by major parties and escalating violence, which has left 73 people dead since late October.

Oscar Fernandez-Taranco, the United Nations' assistant secretary for political affairs, made the comments after three days of talks with the Bangladesh government, opposition parties and the election commission.

Bangladesh's former military dictator Hussain Muhammad Ershad threatened to kill himself Thursday after security forces besieged his home following his decision to boycott next month's elections.

"I have loaded four pistols and I've told the government that if they play any tricks with me, I will kill myself," Ershad told a local television crew during an interview inside his home in the early hours.

Opposition activists derailed a train in Bangladesh Wednesday, killing three people, as part of a campaign against elections due to be held next month, officials said.

Three coaches and the engine of the express train toppled off the tracks in the northern district of Gaibandha, trapping dozens of passengers, police and railway spokesmen said.

Another major Bangladesh political party Tuesday announced a boycott of the upcoming general election, declaring the country was on the "brink of disaster" as seven more people were killed in poll protests.

Former dictator Hussain Muhammad Ershad said his Jatiya Party, the country's third largest and a key ally of the ruling Awami League, would not contest the January 5 elections, following in the footsteps of the opposition alliance.

Bangladesh's 18-party opposition coalition confirmed Monday it would boycott a general election scheduled for January just hours before a final deadline for nominations, plunging the volatile country into political uncertainty.

"There is no question of us filing nominations for the January 5 election under the present circumstances. We're not going to take part in the January 5 elections," Shamsher Mobin Chowdhury, a vice president of the Bangladesh Nationalist Party (BNP), told Agence France Presse.

United Nations rights chief Navi Pillay on Sunday said she was deeply worried by the "shocking" pre-election violence rocking Bangladesh, urging parties on both sides to peacefully resolve their differences over the January 5 polls.

The U.N. High Commissioner for Human Rights also voiced concern about the detention of key opposition leaders in the unrest, which has killed 50 people since late October when the government first announced the date of the general elections.

The European Union on Saturday called for an end to deadly pre-election violence in Bangladesh and said the bloc was willing to consider sending observers to the January 5 polls.

EU foreign policy chief Catherine Ashton said she remained "concerned" about the anti-poll unrest that has killed 20 people since Monday, bringing the death toll to 50 since late October when the government first announced the date of the general elections.

Two people were shot dead as officers opened fire during clashes with thousands of Bangladeshi opposition supporters amid escalating protests against elections slated for January, police said Saturday.

One demonstrator was shot dead by officers Saturday and another died late Friday as police used live ammunition, rubber bullets and tear gas to disperse protesters.

A teenager was killed and 17 people suffered burn injuries after a suspected Bangladesh opposition supporter hurled a petrol bomb into a crowded bus Thursday, amid escalating protests against elections scheduled for January.

Passengers jumped from the windows -- some engulfed in flames -- as the bus veered off the road and crashed into an electricity pole in the Bangladeshi capital Dhaka, police said.

An United Nations envoy will visit Bangladesh to hold talks with political parties about ending an election standoff that has sparked deadly violence, an official said Thursday.

U.N. assistant secretary general for political Affairs Oscar Fernandez-Taranco will arrive on December 6 to hold discussions on "election preparations", Foreign Secretary Shahidul Haque told Agence France Presse.