Iran claimed extensive air strikes against northern Iraq today, and both combatants reported renewed fighting and heavy casualties in the southwestern Iranian cities of Abadan and Susangerd.

Iran said its U.S.-made warplanes hit five targets in northern Iraq, destroying a factory, ammunition depots, a radar antenna and power generating facilities.

The reported air strikes came days after Iraq was said to have resumed oil exports through its 700,000 barrel-a-day capacity Turkish pipeline, which snakes north and then west from the Iraqi oil center of Kirkuk.

Iranian jets also struck at petrochemical and refinery construction projects in northwestern Iraq in the last two days. Yugoslavia's Tanjug news agency said three Yugoslavs working there were killed Tuesday.

The official Iranian news agency, Pars, reported 440 Iraqi troops killed in fighting near Susangerd and Abadan.

Meanwhile, an Iranian Oil Ministry spokesman said in a broadcast statement that Iran will attend the upcoming Organization of Petroleum Exporting Countries conference in Bali, Indonesia, and will raise the issue of its oil minister, who was captured by Iraqi troops in Khuzestan in late October. Iran has accused Iraq of torturing Oil Minister Mohammed Javad Tondguyan.

In another development, the English-language Baghdad Observer newspaper reported that Iraq is building a vast earth wall almost 60 miles long in Khuzestan Province to protect its forces against floods from heavy rain or Iran's deliberately opening a reservoir to flood the area.