For the Belgians all seemed lost. Fearing the total disintegration of the army, Leopold called for international support on 8 August. Sylvain Van de Weyer was sent to attempt to solicit support from Great Britain while François Lehon was sent to France. Although the British government was reluctant to send troops to support Belgium, the French immediately dispatched a force without informing the other Great Powers. The movement of French troops into Belgium particularly worried the British, who felt that it could represent a threat to Europe's balance of power. The French army under Marshal Étienne Gérard crossed the border the next day. The Dutch had taken a risk by invading Belgium without the support of their allies: Russia had wanted to assist but was having trouble suppressing the Polish revolution, and Prussia would not risk sending troops without Russia being able to secure its western borders; now they faced a possible war with the French. After an intervention by the British diplomat Robert Adair, the Dutch halted their advance and a ceasefire was signed on 12 August. The last Dutch troops returned to the Netherlands around 20 August, whilst only Antwerp remained occupied.