Zimbabwe's foreign minister warned a group of Western diplomats Monday that the government would not hesitate to expel them if they gave support to the opposition, and the U.S. ambassador walked out of the meeting, envoys said.

Foreign Minister Simearashe Mbengegwi told them that Western embassies had gone too far by offering food and water to opposition activists who were jailed last week.

President Robert Mugabe's government is under increasing international criticism for its treatment of the opposition, with activists alleging police have disrupted their gatherings and beaten their leaders. Opposition leader Morgan Tsvangirai was among those allegedly assaulted when police broke up a March 11 prayer meeting.

Mbengegwi, who had summoned the envoys to a meeting, read a terse statement that said the Vienna Convention governing diplomatic behavior prohibited foreign ambassadors from involvement in the internal affairs of the host nation, and Zimbabwe would not hesitate to use that provision to expel them.

When Mbengegwi refused to respond to questions, U.S. Ambassador Christopher Dell walked out of the meeting, according to diplomats who spoke on condition of anonymity because the session was closed.

Pressuring diplomats would make it harder for the international community to keep tabs on a government accused of repressing its people and ruining its economy. Over the weekend, Zimbabwe prevented opponents from leaving the country and has long severely restricted the press.

Earlier, Dell suggested there was a split in Zimbabwe's security forces, with police reluctant to carry out a crackdown on the opposition and Mugabe relying on youth militias and agents from the feared Central Intelligence Organization.

Dell told the British Broadcasting Corp. that Mugabe last week spoke to the youth movement of his party and authorized it to use any means available against the opposition.

"What we believe is that we're witnessing a major split inside the security forces, where the regular police, the real police, the professional police of Zimbabwe, are reluctant to carry out such orders, and therefore the regime is increasingly relying on youth militias and special agents from their Central Intelligence Organization, the CIO of Zimbabwe," Dell said.

"And I'm certain that the people of Zimbabwe, when the time comes, will ultimately hold him accountable for comments like that and his responsibility for the, for unleashing this violence over the last week," he said.

Also on Monday, government opponents said the family of an opposition militant killed by police was forced to bury him at their rural home because the administration feared demonstrations at a planned ceremony in the capital.

The government insisted that demonstrator Gift Tandare — killed as police disbanded the March 11 meeting organized by Zimbabwe's political opposition — was buried in the countryside at the family's request and that the state assisted with the funeral arrangements and expenses.

Opposition spokesman Eliphas Mokunoweshure called the government explanation "nonsense."

Members of the opposition said the Tandare family was coerced by CIO agents into holding the funeral in the Mount Darwin district, 95 miles northeast of Harare.

State television said most of the funeral expenses were paid by the ruling party lawmaker for Mount Darwin, Saviour Kasukuwere, a wealthy businessman. It denied Tandare's body had been seized from a funeral home.

Hundreds of mourners and democracy activists have gathered at Tandare's home in the Harare township of Glen View since his death. On March 13, police tried to quell mourners blocking streets and beating drums around Tandare's home in the township, an opposition stronghold. Two were injured by police gunfire.

Nelson Chamisa, aide to Tsvangirai, was assaulted at Harare International Airport by state agents using iron bars on Sunday as he was leaving to attend a meeting in Brussels, Belgium, members of the Tsvangirai's Movement for Democratic Change said.

The alleged assault followed the re-arrests at the airport Saturday of three opposition activists, who were allegedly assaulted along with Tsvangirai and Chamisa on March 11.

The latest violence has drawn new attention to a deteriorating situation in the southern African country, where the increasingly autocratic Mugabe is blamed by opponents for repression, corruption, acute food shortages and inflation of 1,600 percent — the highest in the world.

Mugabe, 83, has rejected the international condemnation following the arrests and alleged beating. The president accused the opposition party of resorting to violence sponsored by former colonial power Britain and other Western allies to oust his government, a newspaper reported Sunday.

"We have given too much room to mischief-makers and shameless stooges of the West. Let them and their masters know that we shall brook none of their lawless behavior," Mugabe was quoted as saying in the state Sunday Mail.