The United States has commended the tens of millions of Bangladeshis who voted in Bangladesh's 11th parliamentary election on December 30, as well as the decision of all major opposition political parties to participate.

The US also described it as a "positive development" after the boycotted election of 2014 and strongly encouraged all parties to refrain from violence and requested the Election Commission to work constructively with all sides to address claims of irregularities.

"The United States remains deeply invested in the future of Bangladesh and its democratic development," said Robert Palladino, Deputy Spokesperson at US Department State in a statement on Bangladesh election on Tuesday.

Palladino said the United States is Bangladesh's largest foreign investor, largest single-country market for Bangladeshi exports, and home to a large community of Americans of Bangladeshi origin.

"In this light, we note with concern credible reports of harassment, intimidation, and violence in the pre-election period that made it difficult for many opposition candidates and their supporters to meet, hold rallies, and campaign freely," said the Deputy Spokesperson.

The US said they are also "concerned" that election-day "irregularities" prevented some people from voting, which undermined faith in the electoral process.

"Bangladesh's impressive record of economic development and respect for democracy and human rights are mutually reinforcing, and we look forward to continue working with the ruling government and opposition towards advancing these interrelated goals," said Palladino.