Dodging mortar shells on the Iran-Iraq front. Iranians show high morale, better artillery

``It's raining. That's good news. Within a few days, Iraqi aircraft will be stuck to the ground and their armored divisions will skid in the mud,'' says an Iranian Army officer, as we cross a slippery pontoon bridge on the Karun River. It's 3:00 a.m., and a few miles south the battle between Iranian and Iraqi forces is raging. The fighting is in its third week since Iran launched a fresh assault. There is no sign it will end soon. From here the battle looks like a fireworks display, with flashes lighting up the sky.

After a few hours of rest in an underground bunker, our group of Western correspondents is taken to the front - seven miles southeast of Basra, on the eastern bank of the Shatt al Arab waterway. The battlefield is a marshy area dotted with palm groves. After crossing the international border, we pass the formidable defense lines Iraq lost on Jan. 9 and 10.

It seems clear that the Iraqis suffered a severe defeat here. Iraqi defenders were apparently caught by surprise, and abandoned considerable quantities of arms.

On this correspondent's fifth visit to the front since the war began in September 1980, the most striking feature is the renewed strength of Iranian artillery.

Iranian troop morale appears extremely high. The Iranian fighters contend they will defeat Iraq for good within three months. Unlike in previous offensives, the Iranians do not appear to be short of military supplies.

Iraq has thus far managed to contain Iranian advances along a defense line some seven miles southeast of Basra. The Iranians seem to be preparing for a new thrust against Basra, but that, say Western military attach'es in Tehran, will require crossing another formidable Iraqi defense line.

No Iraqi aircraft are in sight. ``We now have a very efficient air defense,'' says Ali Hosseini, a Revolutionary Guard who introduces himself as commander of Iranian troops in the sector. ``This has allowed us to shoot down 60 Iraqi fighter-bombers since the beginning of this offensive,'' he claims. Mr. Hosseini refuses to say whether his troops are using US-supplied Hawk antiaircraft missiles.

He says his troops do not intend to occupy Basra itself, but to cut all roads leading to the city. ``The only places we would like to take are the Shiite holy city of Karbala [in Iraq] and Jerusalem,'' he adds.

To Western observers, the Iranian troops appear disorganized. But they display a remarkable knack for improvisation, which seems to compensate for their lack of a classic military chain of command.

Our four-wheel-drive car runs along a narrow dam in the middle of the huge artificial pond known as Fish Lake. The Iraqis flooded this area west of the border in 1982 to deter Iranian troops from launching an assault against Basra. Mortar shells are raining down, but the Iranians seem to think nothing about their own lives.

If the Iranians were to succeed in pushing ahead significanty on the river's eastern bank, they would soon be able to shell the Basra-Baghdad highway. Such a move would virtually cut Iraq in two.

On our way back to the border our driver gets lost in the labyrinth of dams in Fish Lake. Seconds later, just as we depart, a shell hits the place where we were parked.

We eventually reach Khorramshahr where we have the opportunity to talk to a group of Iranian combatants.

``We have to defeat the Iraqis once and for all,'' one says, ``because if we sign a peace treaty with them they will again attack us in the future. And believe me,'' he adds, ``we will win the war .... You Westerners have always underestimated the strength of our revolution.''

A regular Army soldier says ``We provide the logistic support ... but we're not really engaged in the fighting. Those Revolutionary Guards have an incredible courage and dare to do things that we don't.''

Later, in the city of Ahvaz, we're shown a group of about 1,000 Iraqi prisoners of war who have been taught to chant revolutionary Iranian slogans. We also meet with captured Iraqi officers.

An Iraqi pilot whose Soviet-made MIG-23 aircraft was shot down above Fish Lake confirms that Iranian air defense has dramatically improved in recent months. But he says he doesn't know the type of missile that hit his plane.