By DEXTER FILKINS
The tanker was seized in the evening by agents with the American-trained border protection force at the Iraqi town of Badra, after crossing at Munthirya on the Iraqi border, the official said. According to the Iraqi official, the border police found several thousand partly completed ballots inside.
The official, who spoke on the condition of anonymity because he was not authorized to speak publicly, said the Iranian truck driver told the police under interrogation that at least three other trucks filled with ballots had crossed from Iran at different spots along the border.
The official, who did not attend the interrogation, said he did not know where the driver was headed, or what he intended to do with the ballots.
The seizure of the truck comes at a delicate time in Iran’s relations with both Iraq and the United States. The American government has said Iranian agents are deeply involved in trying to influence events in Iraq, by funneling money to Shiite political parties and by arming and training many of the illegal militias that are bedeviling the country.
Agents of the Iranian government are believed to be supporting the two main Shiite political parties here – the Supreme Council for the Islamic Revolution in Iraq and the Dawa Party -with money and other assistance. Both parties support a strong role for Islam in the Iraqi state; however, compared with the Iranian government itself, which is a strict theocracy, the Iraqi version is relatively moderate.
In recent months, American officials in Baghdad and Washington, along with their British counterparts, have contended that sophisticated bombs have been smuggled across the border from Iran, and that some of them have been used against American and British soldiers. The bombs are thought to be far more sophisticated than most of the powerful but rather rudimentary ones used to attack American tanks and convoys here.
At a news conference on Tuesday, hours before the ballot seizure, the American ambassador in Baghdad, Zalmay Khalilzad, spoke of what he said were overt Iranian attempts to influence events in Iraq.
“Iraq is in a particularly difficult neighborhood,” he said. “There are predatory states, the hegemonic states, with aspirations of regional hegemony in the area, such as Iran. There are states that fear success of democracy here – that it might be infectious and spread.”
“We do not want Iran to interfere in Iraqi internal affairs,” Ambassador Khalilzad said. “We do not want weapons to come across from Iran into Iraq, or training of Iraqis to take place.”
Mr. Khalilzad has been authorized to speak with the Iranians on the subject of Iraq, but said Tuesday that he had not yet done so.
Northwest of Baghdad, four American soldiers were killed when their patrol struck a mine, the American military command said, offering no further details.
In a message posted on the Internet, the Islamic Army of Iraq, an insurgent group, claimed to have attacked an American convoy and killed a number of soldiers near Abu Ghraib, west of Baghdad. It was unclear whether the posting was referring to the same attack.
The same group posted another Internet message calling on resistance fighters to refrain from attacking polling stations on election day, to “save the people’s blood.” The group urged Iraqis to continue killing American soldiers.
“This does not mean that we approve of what is called the political operation,” the statement said, referring to the election.
Both Islamic Army postings were translated by SITE, a Washington organization that tracks Islamic militant groups.
Despite the disavowal of violence on Election Day, the prospect of electing their own representatives to the Parliament appears to have driven a wedge into the Sunni-backed insurgency. While the Islamic Army called for a cessation of attacks on polling centers, an Internet message posted this week by five militant groups, including Al Qaeda of Mesopotamia, denounced the elections as a “crusaders’ project,” but, perhaps significantly, did not threaten to disrupt them.
At the same time, insurgents in Ramadi, a Sunni city west of Baghdad, have distributed fliers threatening residents with death if they go to the polls. Similar menacing messages have been posted on walls in towns in western Anbar Province.
To protect against insurgent attacks, some 225,000 Iraqi police and soldiers have begun taking up positions around the country, about 90,000 more than during the January election. The Iraqi forces are being backed up by more than 150,000 American troops.
Other security measures began going into effect around the country on Tuesday, including an extended curfew, a prohibition against carrying weapons and a ban on almost all driving.
In other violence, a Sunni Arab parliamentary candidate, Mizhar al-Dulaimi, was killed in Ramadi by gunmen on his way to visit relatives, officials said, and a friend accompanying him was wounded. Jihadist groups have threatened to kill Iraqis who take part in the political process, either as candidates, poll workers or voters.
Mr. Dulaimi was a businessman known for his strong support for the Iraqi resistance to the American occupation, and he participated last month in an Iraqi political reconciliation conference in Cairo. In a recent television interview, he accused Shiites of trying to arrest him on the basis of what he considered a fabricated security case.
So far, the election campaign has been a turbulent endeavor in Iraq. In the past two weeks alone, 11 people associated with a political coalition that includes Ayad Allawi, a former prime minister, have been killed, including one of its leading candidates in southern Iraq. Last Tuesday, gunmen stormed five northern offices belonging to the Kurdistan Islamic Union, killing two party members and wounding 10.
It is often hard to distinguish political killings from the terrorism that has become a part of daily life here, but in both cases, the parties have accused rivals of carrying out the attacks.
Khalid al-Khassan contributed reporting from Baghdad for this article, and Kirk Semple from Ramadi.
