Speaking after talks in London with EU foreign policy chief Javier Solana, British Foreign Secretary Margaret Beckett said she and Solana "are gravely concerned about the escalation of the present crisis which now poses a serious threat for both Israel and Lebanon and indeed the wider security of the region."

"We urge all parties to do all they can to address this crisis and to prevent the situation from worsening," she said.

British Prime Minister Tony Blair and Solana have talked to UN General Secretary Kofi Annan to support UN's efforts to arrange as quickly as possible a cease-fire, she said.

On Wednesday, Hezbollah guerrillas in Lebanon captured two Israeli soldiers, and killed eight when Israel sent troops into southern Lebanon on a rescue mission.

Israeli jets hit targets cross southern Lebanon and struck Beirut's international airport, forcing it to close. By Thursday morning a land and sea blockage was in force.

"We call for the urgent release of the kidnapped Israeli soldiers and an end to attacks on Israeli towns and cities," Beckett said.

"While Israel is entitled to do what is required to protect its security," Beckett said, "but it should do so in a way which does not escalate the situation and which is proportionate and measured, conforms to international law, and avoids civilian deaths and suffering."