The ousted president of Honduras has briefly crossed the country's border with Nicaragua, in a symbolic move the US has described as "reckless".
Manuel Zelaya has been in exile for nearly a month after he was forced from his position by a coup, and had previously tried to return by plane.
The interim government has said it will arrest him if he sets foot in Honduras.
Earlier, soldiers fired tear gas at hundreds of Mr Zelaya's supporters who were waiting for him near the border.
Talks in Costa Rica aimed at resolving the political crisis collapsed two weeks ago with no agreement reached.
The best thing is to reach an understanding that respects the will of the people
Mr Zelaya, surrounded by supporters and journalists and talking into a mobile phone, lifted the chain marking the border between Nicaragua and Honduras in the frontier town of Los Manos and walked underneath it.
The BBC's Stephen Gibbs said the military personnel retreated by about 20m (yards) as he did so, apparently unclear how to react.
Mr Zelaya, wearing his customary cowboy-style hat, walked up to a sign reading "Welcome to Honduras" but did not go any further into the country.
Less than 30 minutes later, the ousted leader crossed back into Nicaragua, saying the risk of bloodshed was too great.
"I am not afraid but I'm not crazy either," he told Venezuelan-based TV network Telesur. "There could be violence and I don't want to be the cause."
He told reporters he was prepared to return to the negotiation table with the interim government.
"The best thing is to reach an understanding that respects the will of the people," he said.
The US Secretary of State, Hillary Clinton, has described Mr Zelaya's return as "reckless" and not conducive to "the broader effort to restore democratic and constitutional order in the Honduras crisis".
"We have consistently urged all parties to avoid any provocative action that could lead to violence," said Mrs Clinton.
The interim Honduran President, Roberto Micheletti, said Mr Zelaya's action was "ill-conceived and silly".
At least one man was wounded in skirmishes at the border
Prior to Mr Zelaya's crossing, the army had sealed all roads to the border several kilometres (miles) from the actual crossing point, says our correspondent.
But hundreds of people had still gathered in the area and when the military announced an 18-hour curfew, they began throwing rocks at the soldiers, who responded with tear gas, he adds.
At least one man was wounded in the clashes, during which Mr Zelaya was waiting in a white jeep a few metres on the Nicaraguan side of the border.
Earlier televised footage had shown Mr Zelaya driving in a convoy including Nicaraguan police cars towards the Nicaraguan border with Honduras.
The interim government, led by Mr Zelaya's former ally, Mr Micheletti, has imposed an 18-hour curfew along the Nicaraguan border.
People living close to the border were ordered to stay at home between midday local time (1800GMT) and 0600 (1200GMT) to "keep the peace".
"We can't be responsible for the security of people who, by inciting generalised violence in the country, may be subject to attacks even from their own supporters who may have the sole aim of turning them into martyrs," the military said in a statement.
A night time curfew already extends to the whole of the country.
Mr Zelaya was exiled on 28 June after a crisis erupted over his attempts to hold a vote on changing the constitution.
He insists he remains the democratically-elected leader of Honduras and had previously attempted to return home on 5 July.
On that occasion, his plane was prevented from landing when the Honduran military blocked the runway.
The ousted leader's attempt to return follows the collapse of talks in Costa Rica, mediated by the country's President, Oscar Arias.
Mr Arias had drawn up a detailed plan to facilitate Mr Zelaya's return to lead a national reconciliation government prior to early elections in October.
The proposal also included a general amnesty for crimes committed during this crisis and the setting up of a truth commission to investigate events in the run-up to Mr Zelaya's removal.
Delegates of the interim government reiterated they would not reinstate Mr Zelaya as president but said they would present the Arias plan to Congress.
But since it was Congress that approved the ousting of Mr Zelaya, the move may prove to be of limited importance, says our correspondent.
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