The United States sent electronic warfare planes to the Mediterranean yesterday and alerted the aircraft carrier USS America and battleship USS Iowa in Norfolk that they might be needed to further strengthen President Reagan's hand in dealing with Libyan leader Muammar Qaddafi, administration officials said last night.

Military sources noted that the force being assembled by the United States is not only suitable for striking a retaliatory blow for the terrorists' attacks last week at the Rome and Vienna airports, but is gaining the ability to monitor military moves throughout the region, including the battle readiness of Libyan antiaircraft missiles.

The Pentagon yesterday sent five Navy EA6B Prowlers from their home base in Whidbey Island, Wash., to Norfolk and across the Atlantic to the NATO base at Sigonella, Sicily, officials said. The EA6Bs are packed with gear to intercept communications and to jam radars used to direct the antiaircraft guns and missiles the Soviet Union has sent to Libya.

Administration officials said the America and Iowa, tied up one pier apart at Norfolk, were queried on how soon they could get under way for waters off Libya. New sailing orders have not yet been issued, officials said. Crew members were streaming back to the ships following Christmas leave yesterday, while munitions and other supplies were being loaded.

The Joint Chiefs of Staff have sent a detailed analysis of what targets could be hit in Libya if the president should opt for military action to retailiate for last week's terrorist attacks. However, administration officials said yesterday, Reagan has not yet been briefed on the military options.

Reagan, in Mexicali, Mexico, for a meeting with Mexican President Miguel de la Madrid, was asked if there was any truth to reports that the United States was planning a military response to Libya.

"I'm not aware we are doing anything out of the ordinary at all," Reagan said. "We've had various maneuvers and practices there going on . . . . "

Asked if he meant there was no special buildup under way, Reagan said, "No, you've got to stop listening to Qaddafi." The Libyan leader this week threatened to "attack Americans in their own streets" in response to any retaliation.

In advance of presidential decisions, the Joint Chiefs ordered intensive contingency planning, including sending a second carrier to the Mediterranean to join the USS Coral Sea already there. In that connection, the Pentagon has asked the carrier America how long it would need to get ready to deploy off Libya but has not issued such sailing orders.

If Reagan changes the deployment plan for the America, which was scheduled to leave next month for readiness exercises preparatory to a long cruise, and sends the carrier to the Mediterranean, other warships would necessarily go as escorts. Officials said these escorts, including a cruiser with the latest Aegis antiaircraft capability, were also alerted to the possibility of having to sail to the Mediterranean.

Sources said the future deployment of these ships may be decided at a White House National Security Council meeting today, but it had not been definitely scheduled as of last night.

Officials said military planners at the Pentagon, Central Intelligence Agency and military facilities have been put through a number of "what if" exercises the last several days. These included how the United States could keep two aircraft carriers off the Libyan coast for an extended period to deter Qaddafi from acting against the 1,500 Americans in his country or supporting new acts of terrorism.

Sources said the Joint Chiefs, however, have recommended against striking targets unrelated to the Abu Nidal group, which the State Department said operates out of Libya and is the prime suspect behind the airport shootings.

The chiefs earlier this week considered sending B52s from the United States to attack Libyan targets but rejected that option in favor of attacks by Navy carrier planes and long-range F111 fighter-bombers based in Britain if Reagan should order a strike.

The battleship Iowa, if it ends up off Libya, gives the president the further option of hitting coastal targets on the chiefs' list with 16-inch guns, avoiding the risks of having U.S. bombers shot down and their crews captured.

Once the ships are ready, which would require more than a week for the America, it would take another 10 days for the ships to sail to the Mediterranean.