Please substantiate. An attacker knowing an internal collision of the hash algorithm for m1 and m2 (of the same size...) can construct HMAC(m2,key) from HMAC(m1

Please substantiate. An attacker knowing an internal collision of the hash algorithm for m1 and m2 (of the same size...) can construct HMAC(m2,key) from HMAC(m1,key) without knowing the key?