United States and Salvadorean military officials here advocate increased US financial involvement in this country's 41/2-year civil war. Current military aid is so low and installments arrive so sporadically that it is impossible to plan long-term military strategy, these officials say.
''We don't want to imply that we are dissatisfied with the Reagan administration or the US military. Both have been incredible to us,'' says Lt. Col. Miguel Antonio Mendez, chief of Salvadorean Army operations. ''But we cannot win this war if the Congress does not permit a quantitative and permanent increase in military assistance.''
Last fall Congress appropriated $64.8 million of the Reagan administration's request for $86.3 million in military assistance for fiscal year 1984. The administration is now seeking a $93 million increase in supplemental emergency military aid, and proposes $132.5 million in military aid for fiscal year 1985. Military aid to El Salvador has risen eightfold over the past four years. The rebels, widely regarded as the superior fighters here, have stepped-up guerrilla raids this year, possibly giving the Army a stronger case in requesting fresh military aid.
Fred C. Ikle, US undersecretary of defense for policy, says that it will take ''tens of millions'' of dollars to buy needed military equipment. He has called for a military victory in El Salvador, saying that negotiations alone cannot solve the conflict.
A key problem with US military aid, Lieutenant Colonel Mendez says, is that ''we never know how much we are going to receive, when we are going to receive it, or if it will even arrive. This makes the war very difficult to fight.''
One senior US official says, ''My biggest disappointment is the inability or unwillingness of my government to come up front and fund this war. This unreliable funding has undesirable effects, such as a loss of initiative, corruption, and the inability to plan strategically.''
New US aid, US and Salvadorean officials say, will be used to strengthen:
* Tactical mobility on land, in the air, and along the coast.
control and intelligence facilities.
* Integration of air strikes and artillery fire with ground troop operations.
* Maintenance of a permanent military training base within El Salvador.
Military ground and air assaults were severely hampered by lack of air, ground, and water transport vehicles, Mendez and other Salvadorean military officials say.
''When I commanded the Belloso battalion and the terrorists made a military strike, we had to wait hours and sometimes an entire day for transport to be provided to us,'' he says. ''The Belloso only has four trucks of its own, but it needs 35 trucks to move its 1,000 men.''
The Belloso battalion is one of the three US-designed Immediate Reaction battalions that were created to respond quickly to guerrilla strikes.
''We don't have any Medivac (medical evacuation helicopters) helicopters,'' Mendez says, ''so of the soldiers who are seriously wounded in the field, 2 out of 3 die. In Vietnam, only 1 out of 10 American soldiers died from their wounds. In addition to four Medivac helicopters, we need another 10 Huey helicopters.'' The Army has 19 Huey helicopters now.
The guerrillas here also note that the Army is hampered by lack of helicopters. Without helicopters, they say, Army troops can be excluded from whole sections of the country.
''With an increase in guerrilla strength and control,'' one guerrilla says, ''the Army needs a further increase in helicopters.''
Military officials here say they also need more patrol boats to interdict arms shipments they contend arrive from Nicaragua. The Salvadorean Navy has not found any such alleged shipments, but guerrillas freely admit to receiving some supplies from outside the country.
Salvadorean military officials also hope to improve their ground and air communications system. They say they need many more field radios and central communications centers.
''We have rapidly expanded the size of the Army,'' says Mendez, ''but have not kept pace with our logistical supplies.''
The Salvadorean Army numbers some 32,000 men - tripling its size since the conflict began.
The US and Salvadorean military hope to set up a permanent military training center where US advisers will give basic instruction to 1,000 Salvadorean recruits each month, according to officials here. The center may be located in La Union, where training of a small number of recruits has already begun. Two additional centers - one at Zacatecoluca and another at Sonsonate - are also under consideration, officials here say.
The centers would provide recruits with five weeks of basic instruction in first aid, arms handling, field behavior, and close-order drill, these sources say.
''We need to begin to train individual recruits rather than (the standard practice of training) whole units,'' one military observer here says.
A shortage of ammunition is also a problem, officials here say. But they refuse to provide estimates of how much ammunition is required for the armed forces.
The Air Force, which has tripled the number of daily strikes in guerrilla-held and conflictive zones in the past few weeks, according to military officials, is apparently in need of new 250- and 500-pound bombs.
''Primarily,'' Mendez says, ''we are short of specialty ammunition, although we have had to cut back slightly on all of our operations to protect our reserves.''
Mendez concedes that the insurgents' resources are far below the Army's level. ''But they are terrorists and terrorists don't need equipment,'' Mendez says.
The military has stepped up the pace of the air war, apparently trying to push civilians out of rebel zones.
''It has become popular to compare our strategy to that in Vietnam,'' Mendez says. ''This is unfair. We are not attempting to move the sea from the fish because there is no sea. There are only fish.''
In an effort to isolate the insurgents, the Army also hopes to use increased aid to expand its psychological war unit, called OPSIC. The unit is headed by Mendez.
Spread over Mendez's desk are pamphlets exhorting guerrillas, who the pamphlets diplomatically call ''terrorists,'' to surrender and return to the society. These pamphlets are dropped by light aircraft over guerrilla-held territory. The dropping of the pamphlets is often accompanied by the broadcasting of popular Latin music from speakers attached to the plane. Both Salvadorean and some US officials appear to believe that those civilians who are not integrated into the guerrilla forces are being help in guerrilla zones either against their or because they don't know they should get out.
''The terrorists don't permit the people to read these,'' Mendez says, pointing to the pamphlets.
A guerrilla fighter from the Guazapa Volcano says of this military campaign: ''The dropping of the pamphlets over our territory in the midst of all this bombing illustrates how how out of touch the Army is with the people.
''Do you think the people trust the Army after they are bombed and massacred by government troops? Do you think the Army has any credibility when they lie on the radio and in their communiques about battles which everyone who lives here knows never took place?''
But he adds: ''I will have to admit people are thrilled when the pamphlets are dropped. They run out and collect as many as they can. Toilet paper is in short supply.''