The Obama administration and its European allies are weighing their options for greater involvement in Libya, including sanctions against warlords and an armed international force to help stabilize the North African country, diplomats said Tuesday.

With Egypt and the United Arab Emirates secretly cooperating in airstrikes in Libya in the last two weeks, diplomats will meet Wednesday at the United Nations Security Council to consider joint action aimed at defusing the conflict before it grows worse and aggravates regionwide instability.

Fear of a broader Mideast struggle between supporters and foes of Islamist groups “is forcing some rethinking,” said a European diplomat who asked to remain unidentified, citing diplomatic sensitivities. “It seems clear we need to start doing something differently.” […]