Adm. Patrick M. Walsh, vice chief of naval operations, was nominated as commander of U.S. Pacific Fleet by Defense Secretary Robert Gates yesterday.

He would replace Adm. Robert F. Willard, who was nominated March 18 to become commander of the U.S. Pacific Command, succeeding Navy Adm. Timothy J. Keating.

Both nominations require Senate confirmation.

Willard's new assignment would place him in command of 300,000 military personnel from the Navy, Army, Air Force and Marines.

There are 141 ships, 39 submarines, 360 Air Force planes, 900 naval aircraft, 250 Army aircraft and 600 Marine aircraft in the Pacific Command.

It is the oldest and largest U.S. unified command and covers half of the globe or 36 countries from the West Coast of the United States to the East Coast of Africa and from the Arctic to Antarctica.

Under Keating's watch, the biggest potential threat in the region has been China, whose military budget increased 15.8 percent from 2003 to 2007, and North Korea, which recently launched a new long-range missile and is threatening to restart its nuclear program.

A spokeswoman at Pacific Command at Camp Smith said there has been no announcement concerning the future of Keating, who has led the Pacific Command since March 2007.

Walsh graduated from the Naval Academy in 1977 with a bachelor of science degree. He also holds advance degrees from Tufts University.

A naval aviator, Walsh was a member of the Navy's Blue Angels flight demonstration squadron and flew combat missions in the 1991 Desert Storm conflict. He has commanded a carrier air wing, Naval Forces Central Command and the 5th Fleet.

Willard's previous command positions include vice chief of naval operations; commander of U.S. 7th Fleet in Yokosuka, Japan; and commander of Carrier Group 5 aboard the USS Kitty Hawk.

The current deputy commander at Pacific Command, Air Force Lt. Gen. Douglas Fraser, is slated to become the new head of U.S. Southern Command. If confirmed by the U.S. Senate, Fraser would be the first Air Force leader of SouthCom.

Since 1958, when the Pacific Fleet was established as a separate command from the Pacific Command, there have been at least five admirals who held the two jobs, the last being Thomas Fargo in 2005.