WASHINGTON--American forces have seized the initiative on Guadalcanal and are forcing the Japs into retreat, the Navy reported today after revealing that U.S. submarines pounding away at enemy supply lines have sunk seven Jap ships and damaged three others--including a converted aircraft carrier.

Paced by fighter planes and dive bombers which silenced enemy artillery, the American ground forces sprung a small-scale offensive and at one point a band of Marines made a two-mile advance.

The attack was launched to the west of Henderson Airfield and a "small force" of Marines succeeded in driving across the Mantanikan River.

"...The Japanese were reported to be retreating slowly," a communiqué said.