Let Omega there exists 0 be an open bounded domain in R-N (N >= 3) and 2*(s) = 2(N-s)/N-2, 0 < s < 2. We consider the following elliptic system of two equations in H-0(1)(Omega) x H-0(1)(Omega): -Delta u-tu/vertical bar x vertical bar(2) = 2 alpha/alpha+beta vertical bar u vertical bar(alpha-2)u vertical bar v vertical bar(beta)/vertical bar x vertical bar(3) + lambda v, -Delta u-tv/vertical bar x vertical bar(2) = 2 beta/alpha+beta vertical bar u vertical bar(alpha)vertical bar v vertical bar(beta-2)v/vertical bar x vertical bar(3) + mu v, where lambda, mu > 0 and alpha, beta > 1 satisfy alpha + beta = 2*( s). Using the Moser iteration, we prove the asymptotic behavior of solutions at the origin. In addition, by exploiting the Mountain- Pass theorem, we establish the existence of solutions.