European Union foreign policy chief Javier Solana has been met by an angry crowd of Serbs in Kosovo, a week after violent riots killed 28 people.
Mr Solana was barred from entering a refugee apartment
A group of Serbs, driven from their homes by the attacks, screamed at Mr Solana when he visited Kosovo Polje, saying he had failed to protect them.
Mr Solana urged them to be brave and to stay in Kosovo despite difficulties.
His visit coincided with the fifth anniversary of Nato air strikes which forced Serbia's army to leave Kosovo.
He was Nato's secretary general during the two-and-a-half month campaign.
Following the air strikes, Kosovo - nominally still a part Serbia - was placed under UN administration, reviving the majority Albanian community's hopes for eventual independence.
More than 1,000 Albanians gathered in provincial capital Pristina on Wednesday to mark the anniversary and thank Nato troops for stopping the attacks by Serb forces which left thousands dead.
They gave flowers to Nato peacekeepers and international police officers and held banners calling for an end to the recent attacks.
Hundreds of people from both communities were injured in last week's riots.
As the violence spread across the province, more than 3,000 Serbs fled their homes and churches, which were attacked by ethnic Albanian mobs.
Mr Solana visited the town of Kosovo Polje, north of Pristina, to see the damage.
"I am appalled by the brutality of the actions," he told residents. "It is very, very sad to see."
He added that the international community "cannot tolerate and will not tolerate" such actions.
But a Serb man, pointing to burned houses in the distance, shouted: "This is your Western politics."
"See what they've done - it happened under your protection," yelled a weeping woman, according to the AP news agency.
The crowd turned back Mr Solana, EU External Affairs Commissioner Chris Patten and the head of the United Nations administration in Kosovo, Harri Holkeri, when they tried to enter a block of flats to speak with displaced Serbs.
Meanwhile, two planes carrying humanitarian aid from Russia to Serbs fleeing ethnic violence in Kosovo have landed in Serbia.
Russia's Emergencies Minister Sergey Shoigu told a news conference in capital Belgrade that Kfor and UN police "have failed to fulfil their pledge to maintain peace and security in the province in line with UN Security Council resolution 1244".
The Russian foreign ministry had previously described last week's ethnic violence in Kosovo as a medieval barbarity, saying it amounted to ethnic cleansing against Serbs.
UN police say more than 200 suspects have been arrested on suspicion of instigating riots since last week.
But as their operations continued, an international policeman and a local officer were shot dead near the village of Luzane, north of the capital, Pristina.
UN police spokesman Derek Chappell said the victims were travelling in a clearly marked UN patrol car when they came under heavy fire on Tuesday night.
The only other attack of this kind in five years of Kfor peacekeeping operations took place in August last year.