The fourth week of Nato's bombing campaign began with an admission from the Alliance that it had accidentally bombed a refugee convoy, leaving Kosovo refugees dead. The media fallout from the event, and attempts to determine exactly how it happened, dominated media coverage of the crisis for several days.

Meanwhile, there was a fresh surge of refugees out of Kosovo, and air strikes across Yugoslavia continued.

Follow the third week of the Nato campaign in this day-by-day guide. Read the main stories, BBC analysis and the best video and audio clips.

Use the options on the left to return to latest news and other current BBC coverage.

(Claimed damage by Day 27)

Nato: 'Ethnic cleansing spreading'
Nato says Yugoslav forces have extended ethnic cleansing operations beyond Kosovo to villages inside Montenegro, as Tony Blair describes the continuing air strikes as a just cause.

• In the belly of a B-52
• Blair: We'll fight to the end
• Nato calls for oil embargo
• UK public 'still supports Nato'
• Apache: The all-weather attacker
• Picture gallery: Adding to Nato's firepower

Analysis
Who will rebuild the Balkans?
Nato and the KLA
Multimedia
Milisav Paic of the Yugoslav Foreign Ministry: "Attempts to demonise Serbia"
Nicholas Witchell: "Little sign of Serbs being deterred from ethnic cleansing"

Nato 'may have killed refugees'
Nato admits its warplanes may have caused civilian casualties in attacks on two convoys in Kosovo.

• Detail of Nato briefing
• Fears grow for disappeared
• Refugees flock to borders
• Bombing threatens Serbs' environment
• Nato 'considered Serbia invasion'
• Kosovo 'grave gangs' used

Analysis
Viewpoint: Martin Bell on the need for clarity
Multimedia
Nicholas Witchell: Nato dropped bombs on tractors
A night in a Belgrade bomb shelter: John Simpson
"Unbearable strain caused by links between Albania and the KLA": Jackie Rowland reports

Refugees face malnutrition
Aid agencies in northern Albania report the first cases of malnutrition among children crossing from Kosovo, as thousands continue to flee. Meanwhile, Nato aircraft again bomb targets across Yugoslavia, with the city of Novi Sad hit hard.

• Clinton: 'Tyrant' Milosevic must go
• New Nato muddle over refugee attacks
• Belgrade runs for peace
• Belgrade severs Albania ties
• Shea: Nato will not admit defeat
• Serbian toxic fumes fear
• Nato's Jamie Shea answers your questions

Multimedia
Jeremy Bowen in Kukes, northern Albanian: "A very sad place"
Nato's Javier Solana: "Peace will be very difficult"
Nato spokesman Jamie Shea: "Nato would never knowingly mislead any journalist"

New refugee exodus
A further 100,000 Kosovo Albanian refugees are believed to be heading towards Macedonia. The US holds a Yugoslav officer prisoner.

• Yugoslav PoW seized
• KLA 'gaining strength in Kosovo'
• Video shows horror of Kosovo killings
• Serbs warned: War criminals face action
• US to call up reservists

From Our Own Correspondent
Matt Frei on how Albania could benefit from war
Chris Nuttall on the Internet war

Raids widen
Nato widens its campaign of air strikes, pounding key sites across Yugoslavia overnight amid political fall-out from its bombing of a refugee convoy in Kosovo.

• Keep ground options open - Robertson
• Nato stonewalls on refugee bombing
• Refugee strike 'brutal crime', says Belgrade
• Montenegro urges end to strikes

Nato's mistake
Nato admits it bombed a refugee convoy near Prizren, leaving Kosovo refugees dead after a pilot mistook the civilian vehicles for Yugoslav military units.

• The Nato pilot describes what happened
• Cook damns Belgrade's 'crocodile tears'
• Images of the refugee attack
• German peace plan gets cool reception

Refugees bombed
Dozens of refugees are reported killed in attacks on two civilian convoys in Kosovo, amid conflicting claims about who is to blame.

• Fears for refugees in Kosovo
• Eyewitness: Albania's lawless borderland
• New management for Radio B92
• Milosevic breaks silence

Refugee exodus
Full BBC coverage of the second week of Nato's action with links to original stories, transcripts + BBC audio and video reports.
BBC reports include: Nato intensifies bombing, central Belgrade and key bridges hit, refugee exodus from Kosovo increases massively, three US soldiers captured by Serbia.

Serbia bombed
Full BBC coverage of the first week of Nato's action with links to original stories, transcripts + BBC audio and video reports.
BBC reports include: First raids, reports of scorched earth policy in Kosovo, Nato loses Stealth fighter, refugees tell stories of atrocities, Nato starts round-the-clock air attacks, Russian mediation comes to nothing.