The United States is concerned about the plight of thousands of people displaced by fighting between troops and ethnic rebels in northern Burma, a US special envoy said Thursday.

“We have seen progress in many ethnic minority areas over the last several months and weeks,” Derek Mitchell told reporters in Rangoon, referring to a series of peace deals between the government and other guerilla groups.

“But in the Kachin state the violence is sticking out as inconsistent with a trend toward dialogue and confidence building and national reconciliation that we’ve seen.”

Fierce fighting in northern Kachin state between government troops and the Kachin Independence Army since June last year has displaced tens of thousands of people.

“The immediate concern that we have is on the issue of internally displaced persons, who by any definition are innocents caught in the crossfire of conflict,” Mitchell said.

The envoy, who met government ministers and opposition leader Aung San Suu Kyi during his latest trip to Burma, urged the government to enable aid to reach those affected. He announced the US would provide $1.5 million in additional funding to the UN refugee agency to assist those displaced.

Civil war has gripped parts of Burma since independence in 1948. An end to the conflicts and alleged rights abuses involving government troops is a key demand of Western nations which have imposed sanctions on the regime.

With Burma preparing for by-elections on 1 April in which Suu Kyi is standing, Mitchell said Washington’s concern was not about who won but whether the polls were free and fair. He described the vote as “a critical moment and a marker towards building trust and confidence on the road towards democracy”.

Asked whether there should be foreign observers, the envoy said that while such monitors could provide “an objective eye”, it was not up to outsiders to say if the outcome was fair.

“It’s actually up to the people of a country in elections to decide whether this is acceptable in terms of being a representation of the popular will, whether it was conducted freely and that they were able, without intimidation, to exercise their right to vote,” he said.

Mitchell however stressed that the elections were not the only factor Washington would take into account when considering whether to ease sanctions.

“The conditions for sanctions and other restrictions are more than these elections or democracy, there are specific issues that have to do with the release of all political prisoners, that have to do with the ethnic minority issues, have to do with other issues,” he said.

Burma’s new government has surprised observers with a series of reforms, including talks with Suu Kyi and the release of hundreds of political prisoners since the end of nearly five decades of military rule last year.