WARSAW (Reuters) - Poland fleshed out details on Monday of "East Shield", a 10 billion zloty ($2.55 billion) programme to beef up defences along its eastern border with Belarus and Russia, saying it hoped to complete the plans by 2028.

The border has been a flashpoint since migrants started flocking there in 2021, after Belarus, a close Russian ally, opened travel agencies in the Middle East offering a new unofficial route into Europe - a move the European Union said was designed to create a crisis.

The Polish defence ministry presented details of the programme, including plans to build fortifications, hubs and telecommunication systems in coordination with other eastern frontline NATO allies - Finland, Estonia, Latvia and Lithuania.

"This makes up one complex system of defensive and deterrent actions. It connects access systems, but we will also purchase and implement modern anti-drone and reconnaissance systems," Defence Minister Wladyslaw Kosiniak-Kamysz said.

"This is the largest operation to strengthen Poland's eastern border, NATO's eastern flank, since 1945," he told a news conference.

Deputy Defence Minister Cezary Tomczyk said the investments would start in the first quarter of 2025 and were expected to be completed by 2028. Poland hopes to tap EU funds for some of the projects.

Poland's previous government built a fence on the Polish-Belarusian border that is more than 180 km long (112 miles) and 5.5 metres (18 feet) high to protect against illegal migration. It is complemented by a system of cameras and sensors monitoring the frontier.

Relations between Poland and Russia have also deteriorated sharply since Moscow sent tens of thousands of troops into neighbouring Ukraine on Feb. 24, 2022. Warsaw has ramped up defence spending in response.

($1 = 3.9177 zlotys)

(Reporting by Anna Wlodarczak-Semczuk, Pawel Florkiewicz and Barbara Erling; Editing by Gareth Jones)