change cell values

Dear R experts,

I have two  matrices (mat1 & mat2) with the same dimension & the cells (row and column) are corresponding to each other.

I want to change cell values to NA given values of the corresponding cells in mat1 and mat2 are both <1.

E.g. both mat1[2,3] and mat2[2,3] are <1, I will put mat1[2,3]=NA, and mat2[2,3]=NA; if either mat1[2,3]>=1 or  mat2[2,3]>=1, I will save both cells.

I tried the code, but not working. Could anyone can help fix the problem?

mat1[mat1<1&mat2<1]=NA
mat2[mat1<1&mat2<1]=NA

mat1=matrix(rnorm(12),3)
mat2=matrix(rnorm(12),3)
mat1

            [,1]       [,2]       [,3]       [,4]
[1,] -1.3387075 -0.7142333 -0.5614211  0.1846955
[2,] -0.7936087 -0.2215797 -0.3686067  0.7328731
[3,]  0.6505082  0.1826019  1.5577883 -1.5580384

mat2

            [,1]       [,2]       [,3]       [,4]
[1,]  0.4331573 -1.8086826 -1.7688123 -1.4278934
[2,] -0.1841451  0.1738648 -1.1086942  1.3065109
[3,] -1.0827245 -0.4143808 -0.6889405  0.4046203

  		 	   		
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