Israel launched its assault and blockade a week ago
Ehud Olmert said that the cross-border raid in which the two soldiers were captured was co-ordinated with Tehran. About 30 people died in a seventh day of conflict, most of them in Lebanon.
US President George W Bush has meanwhile accused Syria of trying to use the crisis to deepen its influence in Lebanon.
"Syria is trying to get back into Lebanon, it looks like to me," Mr Bush said in Washington.
"It's essential that the government of Lebanon survives this crisis. We've worked hard to free - and we meaning the international community - worked hard to free Lebanon from Syrian influence."
The US state department refused to confirm comments by an Israeli ambassador that Secretary of State Condoleezza Rice would travel to the region on Friday.
Israel launched its assault and blockade last Wednesday after the two soldiers were captured.
About 230 Lebanese people have been killed since then - the majority of them were civilians, but the toll includes about 30 soldiers. The number of Hezbollah militants killed is not known.
Twenty-five Israelis have died - 13 civilians and 12 members of the military.
The human cost of the crisis has continued to mount
Israel has frequently blamed Syria and Iran for arming and backing Hezbollah, but Mr Olmert's comments were the first explicit claim of Tehran's direct involvement in the capture of the soldiers, correspondents say.
Mr Olmert said the timing of the incident was not an accident, and the international community at the G8 summit in Russia had fallen for it - discussing Lebanon rather than Iran's nuclear programme.
Earlier, Israel's foreign minister met a UN team trying to negotiate a ceasefire, but said the soldiers' release and the deployment of the Lebanese army in the south would have to precede any ceasefire.
Thousands more foreigners have continued to flee Lebanon as the crisis deepens.
The UN announced that its non-essential staff would join the exodus.
A British warship is currently on its way to Cyprus, carrying the first Britons to be evacuated from Lebanon by sea.
HMS Gloucester picked up 180 of the most needy cases, including children, after docking in Beirut. Up to 5,000 more Britons are expected to follow over the next few days. The US, Canada and other governments were also organising evacuations by land, air or sea.
In other developments:
Lebanese PM Fouad Siniora said Israel was "opening the gates of hell and madness" on his country, and said Israel's response to the soldiers' capture had been disproportionate
Pro-Syrian Lebanese President Emile Lahoud vowed to stand by Hezbollah leader Sayyed Hassan Nasrallah
UN Secretary General Kofi Annan said he expected European nations to contribute troops to a proposed stabilisation force to end the fighting
The UN warned of a humanitarian disaster as Lebanese flee their homes, with air strikes on roads and bridges hampering efforts to help them
Shlomo Goldwasser, the father of one of the missing Israeli soldiers, said he hoped all means - legal or illegal - would be used to get his son Ehud back
As Israel launched fresh air strikes and cross-border attacks on Tuesday, six bodies were pulled from the rubble of a home in the Lebanese border village of Aitaroun, and another family was killed in the coastal city of Tyre.
In one attack, 11 Lebanese soldiers were killed at a barracks east of Beirut.
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The Lebanese army has been ordered not to respond to the Israeli attacks. But Lebanese soldiers have now died in several strikes, including one on the port of Abdeh on Monday in which nine died.
Fresh volleys of Hezbollah rockets landed on northern Israel on Tuesday. One attack killed an Israeli in the town of Nahariya.
Rockets also hit Haifa, Safed, Acre, Kiryat Shemona, and Gush Halav region near Safed, Israeli officials told AP news agency.
Israeli military officials say more than 700 Hezbollah rockets have now landed in Israel since the crisis began.
O mapa assinala a região aproximada onde ocorreram os principais incidentes que deram origem ao conflito.
 
 
Uma semana se passou desde que   Israel respondeu a um ataque do Hizbollah na fronteira  com o Líbano. Nenhum final imediato para o conflito está à vista. Os israelenses, quer seja pelo ar,  mar ou terra investem  pesado contra alvos estratégicos no Líbano. O Hizbollah por  sua vez ataca com mísseis e foguetes contra a região norte de Israel.

O Primeiro Ministro libanês  Fouad Siniora condena os ataques de Israel e diz que eles estão "abrindo as portas de inferno e da loucura". Ele reiterou a posição do governo libanês:  clamou para   o Hizbollah libertar os soldados israelenses, e pediu para que Israel cesse os ataques, os quais chamou de "desproporcionais". 
 
Porém, um general israelense disse que a ofensiva pode continuar ainda durante muitas semanas. O Primeiro Ministro de Israel  Ehud Olmert alegou que os seqüestradores planejavam desviar a atenção do programa nuclear do Irão.

A população civil do Líbano paga o maior preço. Segundo informou-se pelas agências de notícia, cerca de  200 civis foram mortos nos últimos sete dias no Líbano. Em conseqüência do fogo de Hizbollah, pelo menos 24 israelenses foram mortos, inclusive 9 civis que estavam na estação de trem de Haifa. Morreram 30 soldados libaneses  antes mesmo de entrar em combate contra unidades israelenses. 

As Nações Unidas (ONU) quer que  uma força de paz internacional seja colocada na parte sul do Líbano para fazer o  Hizbollah parar de disparar mísseis contra  Israel. A força atuaria como uma força de estabilização contra ataques de ambos os lados do conflito.

Segundo a ONU, 500 mil  pessoas no Líbano saíram de suas casas, forçadas pela violência, que pode culminar num desastre humanitário. 

Uma equipe de ONU esteve em Israel na terça-feira (18), para conversar sobre  um possível acordo de cessar-fogo. O representante do governo repetiu a exigência dada por Israel para combinar um cessar-fogo:   os dois soldados israelenses raptados devem ser libertados e o governo libanês deve colocar suas tropas no sul do Líbano. O Líbano alega que colocar seus soldados nessa região pode desencadear uma guerra civil no país.

Os militantes de Hizbollah   dispararam na terça-feira (18)  foguetes contra  cidades ao   norte de Israel. Haifa, Acre, Kiryat Shemona e a região de Gush Halav foram atingidas. Um israelense foi morto. Militantes do Hizbollah fizeram comparações entre os "inimigos israelenses" que eles mantêm presos, sem julgamento, com os prisioneiros da Baía de Guantanamo; segundo  eles, uma situação semelhante.

Na terça,  caminhões de transporte foram  mais uma vez alvejados por aviões de guerra.   Segundo Israel os caminhões transportavam mísseis para o Hizbollah. Os militares israelenses dizem que desde o começo do conflito o Hizbollah já disparou 750 foguetes, mísseis ou morteiros.

Centenas de estrangeiros foram evacuadas do Líbano, por intermédio de qualquer transporte disponível. Barcos,  helicópteros e   ônibus foram usados por vários países europeus e os EUA para transportar os seus cidadãos para fora do país.