MANILA, April 17 -- Even before the proposed military access agreement between the Philippines and the United States is signed, there are already indications that its legitimacy will be challenged both in the country's highest court and legislature.

On Sunday, the Bayan Muna (Country First) Party announced that it will question the constitutionality of the agreement in the Supreme Court (SC) once it is signed.

Both Manila and Washington have expressed the hope that the new access agreement, officially called Agreement on Enhanced Defense Cooperation (AEDC), would be signed during the April 28-29 visit by U.S. President Barack Obama to Manila.

Bayan Muna Representative Neri Colmenares criticized the administration of Philippine President Benigno Aquino for being in a "mad rush" to finish the AEDC in time for Obama's visit, saying the pact is "worse than the bases treaty rejected by the Philippine Senate in September 1991."

"Simply put, it is like a dog's welcome gift to his master. They are trying to move heaven and hell so that Obama would be here for the signing of the AEDC," Colmenares said in a statement.

According to Colmenares, the AEDC will practically bring back U. S. military bases to the Philippines but this time "without a treaty, without rent and without limits as the Americans may use all the Philippine military facilities."

Colmenares said his party is preparing to question the AEDC in the Supreme Court for violations of the Philippine Constitution, particularly on sections about civilian supremacy over the military, the state's pursuit of an independent foreign policy, and the ban on nuclear weapons in the country.

Earlier, Senator Miriam Defensor-Santiago, chairman of the Senate foreign affairs committee, said that the U.S. access to Philippine bases under a new regime of expanded U.S. military presence will have to be covered by a treaty that is subject to scrutiny and concurrence by the Senate.

Santiago, an international law expert, said that the deployment of U.S. military hardware in Philippine territory is not a minor case of details in the implementation of the Philippine-U.S. Mutual Defense Treaty (MDT) signed 62 years ago.

"It is a major subject in itself so it (the new agreement) cannot be classified as an executive agreement but as a treaty to which the Philippine Senate must give its concurrence," Santiago said.

The Constitution prohibits foreign bases on Philippine territory unless provided for by a treaty approved by the Senate.

But Malacanang, the seat of the Philippine government, has maintained that the new security arrangement with the United States is an executive agreement and would not need Senate concurrence.

Chief Presidential Legal Counsel Benjamin Caguioa said that the Philippine panel's position is that the AEDC merely implements the general provisions of the MDT and Visiting Forces Agreement (VFA), the two treaties that have been concurred in by the Senate in separate instances.

"Thus there is no need for the Senate ratification for this implementing agreement," Caguioa said.

The VFA, which allows presence of American military assets in the Philippines during joint military exercises, was crafted after the Senate's rejection of the extension of the bases military agreement in 1991.

Representative Carlos Zarate, also of Bayan Muna, questioned how Filipinos could be sure that U.S. forces would not bring nuclear weapons into the country when the U.S. government maintains a neither-confirm-nor-deny policy as to whether their ships or planes carry nuclear weapons.

Zarate warned the presence of nuclear weapons in the country " will make us a prime target of U.S. enemies."

"They already found a way to circumvent the constitutional ban on the presence of foreign troops in the country through the VFA but now they will further maximize this and increase U.S. troops' presence in the country. So, in truth, the AEDC is a very deceptive deal," said Zarate.

Defense Undersecretary Pio Lorenzo Batino, the chief of Philippine negotiators, said the AEDC is meant to provide " critical and timely support to the modernization of the Armed Forces of the Philippines and the achievement of the country's minimum credible defense posture."

"After 15 years of the VFA and given current realities, challenges and opportunities, the Philippines is ready for a heightened level of defense cooperation. This agreement, which should stand on mutual trust, is an idea whose time has come," Batino said.

In a statement, the Philippine panel said that the United States will not establish a permanent military presence or base in the Philippines and that the U.S. military equipment and assets to be stationed in Philippine military facilities will not include nuclear weapons.

Washington, which has earlier announced plans to "rebalance" its forces in the Asia-Pacific region, has similar arrangements with Australia and Singapore.