The fighting, described as the heaviest since October, started at about 6am and lasted until about 1.15pm. Artillery and multiple rocket-launchers fired across the valley at each other.
The British kept their heads down and were confined to the Vitez base, apart from some Warrior Armoured Infantry Fighting Vehicles which positioned themselves in the town 'in order to ease tension'.
Captain Lee Smart, a spokesman for the British battalion in Vitez, said 'there is a lot of fighting in Vitez and around'.
In the Jablanica area, about 110 km (70 miles) south of Vitez, Croats and Muslims battled for a third consecutive day. The Croatian news agency Hina, quoting an officer from the Bosnian Croat Defence Council (HVO) said 10 HVO soldiers had been killed and several others wounded. Hina said Muslim fighters began the attack and Croats returned fire. It was not possible to obtain a Muslim version of the fighting.
Capt Smart said the attack could have been sparked by Thursday's kidnapping of an HVO commander in the predominantly Muslim town of Zenica, 12km north-east of Vitez, and the slaying of three of his bodyguards.
British sources said a number of journalists staying in rooms above a petrol station a mile outside Vitez reported being evicted by masked Croats just before 6am yesterday, after they had been woken by mortar fire and small-arms rounds shot through their accommodation. The Croats checked their credentials and told them to clear out.