Senior US officials have held talks in Israel aimed at brokering a ceasefire with Hezbollah in Lebanon, on a day when more civilians in both countries were killed in the year-long war.

Lebanon’s caretaker prime minister, Najib Mikati, who had expressed optimism of a speedy settlement “in hours or days” earlier on Thursday, said that Israel’s “ongoing escalation” in his country “does not inspire optimism”.

The country’s health ministry said that Israeli attacks had killed 45 people in the previous 24 hours, amid bombing in the north-east Bekaa valley and infantry battles in the south. In one Bekaa village, eight people were killed from the same family.

In northern Israel, seven people were killed by rocket fire from Lebanon, including four Thai agricultural workers, in the worst civilian losses in Israel on a single day since Israel began its ground incursions into Lebanon on 1 October.

Israel issued its second evacuation order for the city of Baalbek and two surrounding villages in the Bekaa valley on Thursday afternoon, carrying out a series of airstrikes on the village of Durous a few hours later. The evacuation orders had prompted a mass exodus of residents from the city, which is home to a Unesco world heritage site.

Despite the evacuation order and danger from Israeli bombing, some residents remained. In Bednayel, a village on the outskirts of Baalbek, rescuers pulled a corpse out of the rubble of a collapsed building levelled in an Israeli airstrike the night before. Eight people from the same family were killed in the strike.

“The whole village shook. I came here and I pulled my brother out from the rubble. I pulled out pieces of him,” said Fadi, a 30-year-old owner of a gaming cafe, whose house was destroyed and family killed in the airstrike.

He dismissed talk of a pause in the fighting between Hezbollah and Israel, saying: “We don’t want a ceasefire, we want to pray at al-Aqsa mosque [in Jerusalem]. I want to take revenge, from the person who dropped the missile to the one who gave the order, [Benjamin] Netanyahu.”

The bombing and evacuation order also affected the operations of the nearby Dar Al Amal hospital, which sits on the edge of Israel’s designated area of operations in Baalbek. Of the hospital’s usual 700 staff, only 350 remain, the rest being displaced, according to the hospital director, Ali Allam. Three nurses have been killed in Israeli airstrikes over the last month while they were off duty.

Two senior US envoys, Amos Hochstein and Brett McGurk, met Netanyahu at his office on Thursday to talk about a ceasefire proposal for Lebanon. Later, Netanyahu’s office said the prime minister had “thanked our American friends for their efforts” but “made it clear that the main point is not this or that agreement on paper but Israel’s ability and determination to enforce the agreement and thwart any threat to its security from Lebanon, in a manner that will return our residents securely to their homes”.

According to the Israeli state broadcaster, Kan, the US-proposed deal is similar to the agreement which ended the last Israeli-Hezbollah war in 2006. Israel would withdraw its forces from Lebanon within the first week of the agreement. The Lebanese army would be deployed along the border, while Hezbollah would end its armed presence in the south.

Israel would still have the right to target Hezbollah in self-defence and to take steps to ensure Hezbollah does not reconstitute in the south, while Israeli aircraft would continue to be able to carry out aerial reconnaissance over Lebanon. It is far from clear such conditions would be acceptable to either the Lebanese government or Hezbollah.

Thursday’s Hezbollah attack on Israel came in two main salvoes, the first in the morning when a rocket barrage fell on fields around the northern town of Metula close to the Lebanese border. The area has been evacuated but farmers are still allowed to cultivate their land during the day, mostly with migrant workers. Four of the five victims of the Metula barrage were Thai migrant workers and the fifth was an Israeli farmer.

A few hours later, a second salvo of 25 rockets hit an olive grove near Haifa where people had gathered for the harvest. The Israeli health authorities said a 30-year-old man and 60-year-old woman were killed.

In the West Bank, Palestinian authorities said three people had been killed in an Israeli raid. The Israeli army said it was targeting militants in the Nur Shams refugee camp in the West Bank city of Tulkarem, and had killed a Hamas militant who was involved in planning attacks.

A senior Hamas official told Agence France-Presse that the group rejected any proposal for a temporary truce with Israel, an idea reportedly floated at talks in Doha over the weekend. The group is insisting on a permanent ceasefire and the complete withdrawal of Israeli forces from Gaza.

Also on Thursday, Philippe Lazzarini, who heads the UN Palestinian refugee agency Unrwa, accused Israel of severely damaging the organisation’s headquarters in the West Bank’s Nur Shams camp.

The Israeli military, however, denied responsibility for the damage, saying: “The claim that the Unrwa offices in Nur Shams were destroyed by IDF soldiers is false.

“Terrorists planted explosives in the proximity of the Unrwa offices that were then detonated in an attempt to harm IDF soldiers. The explosives likely caused damage to the structure.”

On Monday, Israel passed a law banning Unrwa from operating in the country, which could impair its work in wartorn Gaza.