Thousands of Syrians have recently crossed into Lebanon, the UN say.

联合国称，近期有数千叙利亚人越境进入黎巴嫩。

The UN refugee agency said as many as 2,000 people fled in the past two days.

A resident of the opposition¹ stronghold of Homs told the BBC that soldiers had slit² the throat of her 12-year-old son.

Meanwhile, the UN humanitarian³ chief said she had now been allowed to travel to Syria and would call for "unhindered（不受阻碍的） access for humanitarian aid".

Valerie Amos said she planned to go to Syria on Wednesday.

Former UN Secretary General Kofi Annan is also due to visit Syria at the weekend as joint⁴ special envoy⁵ for the UN and the Arab League. On Wednesday, he will hold talks with league officials in Cairo.

'Screams'

The UN refugee agency (UNHCR) said on Monday that many Syrian refugees - including women and children - had only a few belongings⁶ as they arrived into Lebanon.

Residents of the northern Lebanese town of Arsal said that up 150 Syrian families arrived there on Sunday alone.

"What are we supposed to do? People are sitting in their homes and they are hitting us with tanks," Hassana Abu Firas, from Syria's border town of al-Qusair, told the Associated Press.

"Those who can flee, do. Those who can't will die sitting down," she added.

People fleeing the city of Homs, 15km (nine miles) from al-Qusair, have told the BBC that security forces are committing atrocities⁷ there.

One woman told the BBC's Paul Wood on the outskirts⁸ of Homs that soldiers had killed her son on Friday - a day after rebel fighters withdrew from the Baba Amr district.

"My son's throat was cut," she said. "He was 12."

Her husband said he was hiding about 50m (160ft) away and saw one soldier hold down their son's head with his boot while another killed him.

"I could hear their screams," he added.

The woman said 35 other men and boys from her area had also been detained and killed.