The Reagan administration said today it is considering new sanctions against Panama to force the ouster of strongman Manuel Antonio Noriega, but it appeared no action was imminent. ``Other sanctions are being actively considered,'' said White House spokesman Marlin Fitzwater. However, an administration official, speaking on the condition of anonymity, said ``nothing's imminent.'' On Capitol Hill, meanwhile, two Republican lawmakers introduced legislation that calls on President Reagan to renegotiate the Panama Canal treaties to allow U.S. troops to remain in Panama past the year 2000. The canal treaties negotiated with Panama in 1979 provide for the transfer of the canal to Panama on Dec. 31, 1999. The legislation introduced by Rep. Robert Walker of Pennsylvania and New York Rep. Jerry Solomon would allow independent U.S. action to defend the canal as well as permit U.S. troops to remain in Panama past the year 2000. Separately, Sen. Alfonse M. D'Amato, R-N.Y., said today that Noriega's troops have harassed and beaten canal employees. ``There is a continuing pattern of escalation'' in Panamanian actions against the canal, he said in an interview on ABC-TV's ``Good Morning America.'' He did not elaborate. Beyond applying new sanctions, the administration is raising the prospect that the U.S. military may be used to protect the estimated 50,000 American citizens in Panama against possible harassment by that country's security forces. Fitzwater appeared to open the door to that possibility Tuesday after an incident the previous evening in which Panamanian troops confiscated the tapes of four U.S. television networks and briefly detained several American journalists. Discussing the harassment against Americans, Fitzwater said, ``It has always been a principle that we will protect American citizens as best we can and, while we have said that we don't plan to go in militarily, it's also important to note that there are limits.'' But when President Reagan met with senior advisers Tuesday afternoon to discuss the Panama situation, use of military force was not discussed, according to an administration official who asked not to be identified. The official said other options were discussed for bringing pressure to bear on Panamanian strongman Manuel Antonio Noriega, the de facto head of what the United States considers to be an illegal government. It was not clear whether Fitzwater's comments represented a genuine re-evaluation of U.S. policy or were part of the continuing war of nerves between the administration and Panama's military-dominated government. One major deterrent to military intervention is that any such move would generate a hostile reaction throughout Latin America. Most delegates attending a conference of Latin American representatives in Venezuela on Monday and Tuesday called for the U.S. to exercise restraint. In recent days, the administration has been weighing the possibility of imposing additional sanctions against Panama. U.S. officials, who asked not to be identified, said Reagan could invoke the International Emergency Economic Powers Act, which would give him broad discretionary authority to limit private U.S. transactions with Panama. One example would be the suspension of all air service between the two countries. Over the past month, administration actions have effectively cut off the flow of dollars into Panama, leaving the country near insolvency. Reagan has called on Noriega to step down. There was a new sense of urgency here Tuesday over signs of an accelerating deterioration of the situation in Panama. On Monday, thousands of anti-government demonstrators were routed by government forces with the help of shotguns, tear gas and water cannon. Witnesses said several people were injured and dozens arrested. Later, security agents forced their way at gunpoint into the offices of four American networks at a local hotel and confiscated tapes of the demonstration. Eight foreign journalists, including Americans, were detained for several hours before being released. Shortly before Fitzwater spoke, ousted Panamanian President Eric Arturo Delvalle, whose authority the United States continues to recognize, appealed for the creation of a U.S.-led international force to oust Noriega. Delvalle, who has spent the past month in hiding, made his appeal through Panama's ambassador, Juan B. Sosa, who has been acting as Delvalle's representative in Washington and has refused to relinquish the embassy to a replacement appointed by Panama's new government. While criticizing the violence used against Panamanian demonstrators, the focus of the remarks by both Fitzwater and State Department spokesman Charles Redman was on the harassment of the American journalists. Their comments evoked memories of Grenada when the United States and several friendly Caribbean nations sent forces into that country five years ago and ousted the leftist government there. The U.S. rationale was that hundreds of American medical students on the island faced potential danger. Fitzwater said, ``We are certainly concerned by this threat to Americans and find it a very difficult turn of events and one that is contrary to assurances that we have received in the past.''