The Iraq government said it fired a missile into Tehran on Sunday to retaliate for Iranian artillery attacks that killed 21 people in Iraqi border towns.
Iran vowed revenge, indicating a resumption of the "war of the cities" after an uneasy 2-day truce. A 12-day missile duel directed at each other's capitals killed scores of civilians.
"If the Iranian regime continues its aggression, then our retaliation will continue with all-out strength," an Iraqi military spokesman was quoted as saying by the Iraqi News Agency.
Iran's Islamic Republic News Agency, monitored in Cyprus, confirmed that Tehran was hit again. It said the missile exploded in a residential neighborhood, killing and wounding "a number of civilians." The agency gave no figures.
The news agency quoted an official spokesman as saying, "Iran's Muslim combatants will severely retaliate," and he warned Baghdad residents to evacuate the Iraqi capital. The spokesman, who was not identified, also denied as "pure fabrications" the Iraqi claim that Iran had shelled Iraqi border towns.
An Iraqi military spokesman, speaking on television, said Iran broke the conditions of the city-war truce by shelling civilian areas. He also said Iranian forces launched a ground attack in the central sector of the war front.
"Iraq will retaliate on Tehran for one time, as a warning to the Iranian regime," said the spokesman, who was not identified.
The Iraqis said a single Al Hussein missile, which has a range of 400 miles, was fired into Tehran, 290 miles from the border.
The Iraqi military spokesman said 13 civilians were killed and 70 wounded in Iranian shelling of the town of Halabja, about 130 miles northeast of Baghdad. Another eight were killed and nine wounded in other border towns, a communique said.
In the 12-day war of the cities, Iran reported nearly 200 civilians killed and hundreds wounded, while Iraq reported many civilian casualties but gave no figures.
The Al Hussein missile is named after a Shia Muslim saint. Iraq says the missile is manufactured in Iraq, but Western military analysts believe it is a Soviet-made Scud-B modified to provide the necessary range to reach Tehran.
Iran has used unmodified Scud-B missiles, which have a range of 190 miles, to bombard Baghdad, which is 85 miles from the border.
The Iraqi News Agency said more than 1,000 Iranians were killed in the 3 1/2-hour ground battle in the central sector of the war front. The battle began late Saturday and ended early Sunday.
Iran did not comment on the report, but the Iran news agency reported that in a separate raid farther north, Iranian Revolutionary Guards and anti-government Kurdish guerrillas killed or wounded 450 Iraqis.
The Iraqi News Agency also quoted a military spokesman as saying Iraqi planes "dealt an accurate and effective blow to a very large maritime target," a reference to a supertanker, off Iran during the night.