BRUSSELS, Sept 2 (Reuters) - Poland and Latvia expressed concern on Thursday over Russia"s looming military drills held jointly on Belarus" western border where the European Union accuses Minsk of pushing migrants over to put pressure on the bloc. Poland, Latvia and Lithuania sealed off their eastern borders after several thousand people - including from Iraq, Afghanistan, Congo and Cameroon - got in, crossing on foot from Belarus through dense woods. The EU accused Belarusian President Alexander Lukashenko of blackmail and risking the lives of the migrants for political revenge on the bloc after it had slapped sanctions on Minsk. That came after Belarus forced a Western airplane to land on its soil to arrest a Lukashenko critic on board, part of a sweeping crackdown on dissidents protesting a disputed 2020 presidential election. "What is happening in Belarus is a hybrid attack on our borders where basically the state is kidnapping people, giving them visas and then pushing them into the border area," Latvian Defence Minister Artis Pabriks told the European Parliament. "This is a dangerous thing particularly because of military exercises Zapad 2021. They are colliding in the same place at the borders of the European Union." Speaking at the same hearing, Poland"s EU ambassador said Lukashenko was testing the bloc and warned the situation might get more tense with the Zapad - or "West" - wargames due to start on Sept.10. "Some of the elements of the exercises will be held in the vicinity of EU borders," said Andrzej Sados. "This creates additional risks of incidents." The EU - increasingly restrictive on immigration since Mediterranean arrivals overwhelmed it in 2015 - supports its eastern members in preventing irregular migrants from coming, though rights groups demand help for the people. "We need not only EU coordination but support including the possibility of new sanctions because our borders are under stress," said Pabriks. A deputy foreign minister of Lithuania also demanded further sanctions on Belarus, including restricting access to international financial markets for flag carrier Belavia, which is already blocked from European skies. He said new sanctions should target "Belarusian state entities and persons involved in the smuggling of migrants across the eastern EU border and the abuse of human rights." Belarus said last month the Zapad drills would involve thousands of servicemen, as well as tanks, artillery and aircraft. The annual exercises often unnerve the West but this year the situation is more tense over the migration issue. Lukashenko has said he will no longer hold back migrants after the EU imposed sanctions over the 2020 presidential election and Minsk"s subsequent crackdown on protesters. Some 166 persons - including government ministers, army and security officials, as well as judges accused of playing an active role in the crackdown - and 15 entities are now on the EU"s blacklist, meaning any assets they hold in the bloc are seized and they cannot travel to any of the 27 member states. The broader economic sanctions bar sales of equipment to Belarus that might be used for monitoring of the Internet or telephone calls, and restrict trade in petrol products as well as potash, Minsk"s main export.