Baburam Bhattarai, KP Sharma Oli, Pushpa Kamal Dahal and Madhav Kumar Nepal contest from Gorkha, Jhapa, Rukum East and Rautahat respectively.

Leaders demand a free and fearless environment but say their parties have yet to make official decisions on poll participation.

They aim to become a decisive force for identity-based politics in Tarai after unity.

Sources say three big parties are near agreement on addressing serious human rights violations and extrajudicial killings.

Scientists from Nepal Academy of Science and Technology and National Earthquake Monitoring and Research Centre visited Jajarkot on the third day of the disaster.