Problem install memcached

Hi,
when I try to install memcached "/opt/plesk/php/7.0/bin/pecl install memcached" I get this error

"PHP Warning: PHP Startup: Unable to load dynamic library '/opt/plesk/php/7.0/lib64/php/modules/memcache.so' - /opt/plesk/php/7.0/lib64/php/modules/memcache.so: cannot open shared object file: No such file or directory in Unknown on line 0"

How Can I resolve?

Thanks