hifi engine

Sansui 661 with infinity reference four speakers

So I've been running this amp with a pair of sansui sp-2500x speakers for
A couple years. I recently purchased a pair of infinity reference four speakers that recommend between 25-150 watts. The amp is rated at about 25 at 8ohms and 40 at 4 ohms. The speakers are 6 ohms. Is it safe to run them on this amp or will I ruin the amp and or speakers? Thanks.