KIEV, June 4 – Ukrainian border guards abandoned their posts in Sverdlovsk at the border between Ukraine and Russia, letting pro-Russian rebels take over the border crossing, The Daily Beast reported Wednesday.

This means there is no barrier to stop pro-Russian militia groups from funneling fighters and supplies from Russia into their breakaway territories.

The development suggests that even as Russian President Vladimir Putin is supposed to meet with senior European leaders on Thursday and join the D-Day commemoration in Normandy on Friday, the war in eastern Ukraine may be moving into high gear.