LONDON, Dec 9 (Reuters) - Britain will send 140 military engineers to Poland this month to provide support at its border with Belarus, the Ministry of Defence said, in response to what it termed pressures from "irregular migration". Britain already has personnel in its NATO ally Poland, amid tensions at the EU"s border with Belarus. The bloc says Belarus has flown in migrants from the Middle East to push them to cross the border, accusations Minsk calls absurd. "Our commitment to European security is unwavering and we will always offer support to our allies. This non-combat support will assist Polish efforts to protect their border and pass on vital engineering expertise," Defence Secretary Ben Wallace said. The MoD said that the deployment of the engineers was expected to last until April.