A day after Japan's first ground troops set foot on Iraqi soil, top government officials found themselves urging members of the Liberal Democratic Party to unite and collectively support the dispatch.

The calls came as some senior LDP members reportedly hinted that they might not vote in favor of the deployment of the Self-Defense Forces in upcoming Diet deliberations on the issue.

An advance Ground Self-Defense Force unit arrived in the southern Iraq city of Samawah on Monday evening.

Some LDP members who attended Tuesday's meeting of the LDP Executive Council reportedly said they may not support the party's decision to approve the SDF dispatch.

The Diet must give ex post facto approval of SDF missions to Iraq under a special law that allows Japan to send troops to assist in reconstruction efforts.

"There may be various moves at this stage now, but I think it's necessary for (LDP lawmakers) to solidly unite as a party," Chief Cabinet Secretary Yasuo Fukuda later told a regularly scheduled news conference.

Meanwhile, during Tuesday's session of the National Defense Division of the LDP's Policy Research Council, other party members also reportedly argued that the government should withdraw the SDF troops if it becomes clear that insurgents and terrorists are specifically targeting the Japanese.

But Fukuda said the government should not draw up any specific guidelines to stipulate the conditions under which Tokyo will pull its troops out of Iraq.

"We should make such a judgment after consideration of the full picture of the situation at that time," the government's top spokesman said. "We shouldn't single out one particular example and discuss that."

Another senior government official, speaking on condition of anonymity, said discussing and revealing such guidelines in advance could in fact prompt terrorists to plan attacks that would place the SDF in this situation.

In addition, the official said, that sort of judgment should be made after considering public reactions.

Approval ratings for Prime Minister Junichiro Koizumi's Cabinet are widely considered critical for the fate of his administration, as well as that of the LDP, which will be judged by voters in July's House of Councilors election.

Asked what would determine the completion of the SDF mission in Iraq, Fukuda said the troops could be pulled out once civilian aid experts can freely enter the country and play their respective roles.

The government has argued that it opted to send the SDF, rather than civilian officials and nongovernmental aid groups, to Iraq because the military units can protect themselves and engage in relief activities without requiring logistic support.