The three Baltic countries are asking NATO to permanently deploy about 2,000 army troops to Estonia, Latvia and Lithuania.

Capt. Mindaugas Neimontas, spokesman for Lithuania's chief of defense, says the three countries are presenting the request in a joint letter this week to NATO's supreme allied commander in Europe.

Neimontas says the Baltic countries are asking for a brigade-sized unit, with one battalion of 700-800 troops in each country.

The troops would be stationed in the Baltic region on a rotational basis, similar to NATO's air policing mission, in which the air forces of NATO countries take turns patrolling Baltic airspace.

Neimontas told AP on Thursday that permanent NATO troops are "necessary because of the security situation. It's not getting better in our region, so it will be a deterrent."