Clinton’s message, coinciding with the Sinhalese and Tamil New Year, came weeks after the UN Human Rights Council adopted a US-tabled resolution urging Colombo to probe war crimes charges related to its 2009 defeat of Tamil rebels.
Sri Lanka condemned the resolution as wanton interference in its internal affairs.
“This (new year) celebration brings people together,” Clinton said.
“It also gives Sri Lankans of all backgrounds … an opportunity to help build a prosperous, democratic nation defined by tolerance and respect for human rights.”
Clinton stressed US willingness to support the island’s efforts “to foster national reconciliation and development.”
Rights groups have said that up to 40,000 civilians were killed in the final offensive by Sri Lanka’s Sinhalese-dominated military against Tamil Tiger rebels in 2009.
The two communities share a common new year marking the end of the harvest season and the beginning of the monsoon.
The resolution adopted in Geneva urged Sri Lanka to probe war crimes charges, implement the recommendations of a domestic inquiry into the war and seek UN help for reconciliation with the ethnic Tamil minority.
Colombo has denied its troops were responsible for any non-combatant deaths and refused to allow any independent probe into allegations of military excesses.
Sri Lankan Foreign Minister Gamini Lakshman Peiris is due to hold talks with Clinton in Washington next month.