President Hugo Chávez has announced that foreigners who visit Venezuela and criticise his government will be escorted to the airport and expelled.

In a televised address the Venezuelan leader ordered cabinet ministers to monitor statements by visitors and deport them if they "denigrated" his leadership.

"How long are we going to allow a person - from any country in the world - to come to our own house to say there's a dictatorship here, that the president is a tyrant, and nobody does anything about it?" he said. "No foreigner, whoever he may be, can come here and attack us. Whoever comes, we must remove him from the country. Here is your bag, sir, go."

The threat, made during a six-hour broadcast on Sunday, is one of the strongest warnings to foreign critics since Mr Chávez was elected eight years ago. It came on the eve of the publication of a draft constitution that will propose abolishing presidential term limits, allowing the socialist leader to stand again when his current term ends in 2012.

He has recently signalled an acceleration of his self-described revolution by ordering the armed services to reflect socialist values and telling education officials to purge the "perversity of capitalism" from school textbooks.

Opinions about the politician, an outspoken opponent of US foreign policy and a key ally of Cuba, are sharply divided at home and abroad. Supporters say he is a democrat who has won three landslides, poured his country's oil wealth into social programmes for the poor and restored dignity to Latin America by standing up to Washington. Opinion polls put his approval ratings well above 60%.

Critics say he is wasting billions on unsustainable populist schemes and eroding democracy by bringing the courts, parliament, the armed services and the state media under his direct control. In May the government refused to renew the terrestrial broadcast licence of RCTV, an opposition-aligned TV station, provoking accusations of censorship.

Sunday's attack will further polarise the president's reputation. He did not name any critics but the immediate target was believed to be Manuel Espino, the head of Mexico's conservative ruling party, who on a recent visit to Caracas questioned the president's democratic credentials.

Mr Chávez said he personally did not mind criticism but that in some cases it affronted "national dignity". Hours after his speech the information ministry issued a press release quoting the remarks. It was headlined: "Foreigners who come to Venezuela to denigrate it must be deported."

Some analysts played down the warning. "I still subscribe to the view that what appears to be wrong with Chávez is more bark than bite," said Larry Birns, of the Washington-based thinktank, the Council on Hemispheric Affairs.

"Venezuela is not moving towards an authoritarian regime. It's just that when he speaks Chávez doesn't have a pause button. These sort of remarks cause enormous misapprehension and misunderstanding but don't really represent his convictions."

One western diplomat said Sunday's speech did not signal a crackdown on dissent but did reflect a worrying drift. "One shouldn't overreact, it doesn't change much right now, but it is part of a general trend towards intolerance of criticism."

Foreign journalists and NGOs operate freely in Venezuela and about 80% of the domestic media is in private hands. Mr Chávez's supporters say he has behaved with remarkable restraint given that much of the private media openly backed a coup which briefly ousted him in 2002.

But the climate is changing. The only critical TV channels, RCTV and Globovision, are confined to cable, leaving most viewers to choose between private channels that soft-pedal journalism or state channels that provide fawning coverage of the president.