Sri Lanka on Wednesday accused Western diplomats of favouring the Tamil minority as tensions mounted over a meeting in Colombo between envoys and families who lost loved ones in the country's war.
US and other Western diplomats met on Monday with ethnic Tamil families whose relatives disappeared or were killed during the decades-long separatist conflict that ended in 2009.
Pro-government mobs led by Buddhist monks stormed the meeting at a Catholic Church compound, prompting the US embassy to demand Sri Lanka enforce its own laws on freedom of speech and association.
Sri Lanka's foreign ministry hit back on Wednesday, accusing the diplomats of "lacking in objectivity" by favouring Tamils over the Sinhalese majority and fuelling "mistrust" and division between the communities.
"The ministry wishes to point out that, once again, a certain section of the diplomatic corps appears to be involved in a manner lacking in objectivity, in events organised for a particular region and community," the ministry said in a statement.
The ministry warned the diplomatic community to "be more conscious of local sensitivities when attending events of an emotive nature."
The US embassy had accused police of supporting the mobs who it said "behaved threateningly" towards the families from Sri Lanka's former northern war zone.
France, Germany, Britain and Switzerland also issued a statement on Tuesday backing the US demands for rule of law.
Colombo faces international pressure over allegations its forces killed at least 40,000 Tamil civilians in the final months of the war between the military and rebels fighting for a Tamil homeland.
Colombo has long denied the charge.
Critics have recently accused President Mahinda Rajapakse's government of a renewed crack down on dissent, after it last month banned civil society groups from holding press conferences.
Monday's disruption of the meeting follows recent incidents in which pro-government mobs have broken up US-funded workshops for journalists from the Tamil community.
The murders of more than a dozen journalists and media workers during the decades-long war have remained unsolved for the past 25 years.