BAGHDAD — A senior government official was assassinated in Baghdad today as clashes between Shiite militants and U.S. and Iraqi forces in the capital's Sadr City district left eight other people dead, officials said.

The violence in the embattled area appeared to be a continuation of heavy fighting over the weekend in which about 45 militants and four U.S. soldiers have died.

A showdown between Iraqi forces and the Mahdi Army militia — led by anti-American cleric Muqtada al-Sadr — has increasingly drawn U.S. troops into battle. American commanders are particularly focused on trying to curb a rise in mortar and rocket attacks on the heavily fortified Green Zone in central Baghdad that houses Iraq's government and many foreign embassies.

Overnight clashes resulted in 42 injuries, officials at the Imam Ali and al-Sadr general hospitals said. Eight more were killed and 25 wounded in continuing firefights on Tuesday morning, said the officials who spoke on condition of anonymity because they were not authorized to speak to the media.

AP Television News footage showed men helping women cross the street and children running for cover behind blast walls amid gunshots.

Men helped carry several blood-soaked wounded onto stretchers to a local emergency hospital. Outside the hospital, the dead were placed inside plain wooden coffins.

Also in Baghdad, Dhia Jodi Jaber, director general at the Ministry of Labor and Social Affairs, was hit by a roadside bomb as he left his home on Tuesday morning, the ministry's spokesman Abdullah al-Lami said.

Insurgents frequently target governmental officials and institutions in a bid to disrupt the government's work.

In the southern city of Basra, where the government began its crackdown on Shiite militias last month, Iraqi military commander Lt. Gen. Mohan al-Fireji announced the discovery of a huge weapons cache containing roadside bombs, mortar launchers and Iranian-made weapons.

More details on the number of weapons or how authorities knew they were Iranian-made were not immediately available.

Meanwhile, the trial of Tariq Aziz, one of Saddam Hussein's best-known lieutenants, was scheduled to open in Baghdad on Tuesday.

Aziz is one of eight defendants facing charges in a case dating back to 1992 when the government executed 42 merchants for war profiteering. Others include Saddam's half brother and the dictator's cousin known as "Chemical Ali," who faces a pending death sentence in another case.

A government official, who declined to be identified because he wasn't supposed to release the information, said Ali Hassan al-Majid was hospitalized and will not attend the new trial. He is suffering from diabetes and blood high pressure Al-Majid's lawyer, Badee Izzat Aref, also said Monday that his client was too ill to stand trial.

Elsewhere, a female suicide bomber blew herself up at a bus stop near Muqdadiyah, about 60 miles north of Baghdad, killing one and wounding five people, police said.

In other developments, the Iraqi defense ministry said Serbia had agreed to write off $3 billion in Iraq's foreign debt.

Serbia's move comes after an international conference last week in Kuwait at which Prime Minister Nouri al-Maliki and Secretary of State Condoleezza Rice unsuccessfully pressed Saudi Arabia and other Gulf states to forgive Iraq's debts as a sign of support for Iraq's government.

Iraq has at least $67 billion in foreign debt — the vast majority of it owed to Saudi Arabia, Kuwait, the United Arab Emirates and Qatar.