Iran on Monday defied Lebanon's expulsion order for its ambassador by saying he would stay, further increasing tensions in a country in the crosshairs of the latest fighting between the Iranian-backed Hezbollah and Israel.

Lebanon had declared Ambassador Mohammad Reza Shibani "persona non grata" in an effort to weaken Iran's diplomatic presence and have a charge d'affairs at its embassy instead. But the deadline to leave the country was Sunday.

The Israeli military on Monday said a soldier was killed a day earlier in combat in southern Lebanon, bringing to six the number of troops killed since fighting with Hezbollah started earlier in March.

"Sergeant Liran Ben Zion, aged 19, from Holon... fell during combat in southern Lebanon," the military said. An officer was also severely wounded.

The Israeli army targeted overnight into Monday several towns and villages in south Lebanon as Hezbollah claimed attacks against soldiers in the south and targets in north Israel.

A strike on a Lebanese army checkpoint in al-Amirieh between Tyre and Naqoura, killed a soldier and wounded at least four others. Strikes also targeted Shaqra, Dweir, Zrarieh, Bazourieh, Qaaqaiyet al-Jesser, Yater, Qalaway, Ainata, Harees, Bint jbeil, Hanaway, Baraashit, and a public school in Samaiyeh, while artillery shelled al-Mansouri, Maroun al-Ras, and Yaroun.

As Christians packed churches across Lebanon this Palm Sunday to commemorate their belief in Jesus' triumphal entry into Jerusalem, the renewed war between Israel and Iran-backed Hezbollah weighed on parishioners.

Still, it was standing-room-only at a Maronite Catholic church near Dahieh, in Beirut's southern suburbs, a once-densely populated Shiite district — now emptied by sweeping Israeli evacuation orders and constant airstrikes. In the coastal city of Tyre in southern Lebanon, which has been almost cut off from the rest of the country by Israel bombing surrounding bridges, the peal of church bells and velvety choral music filled the air.

Armed with thick gloves and small plastic crates Kamal, Khalil and Reem jump on two mopeds and head into Beirut's southern suburbs, which see almost daily strikes by Israeli aircraft.

Hands scarred by a thousand bites and scratches, the small rescue team from Lebanese NGO Animals Lebanon uses two-wheelers to navigate streets made narrow by piles of rubble as they search for trapped animals.

An Israeli strike on an ambulance belonging to the Hezbollah-affiliated Islamic Health Committee killed one paramedic and his patient Sunday, the group’s spokesperson said.

The incident came a day after at least nine first aid workers were killed by Israeli strikes on the south and, according to the Lebanese health ministry, some 47 have been killed since the war began.

An Israeli airstrike on a residential building near Beirut's southern suburbs killed at least three Hezbollah members on Monday, a security source told AFP.

The strike "targeted an office used by Hezbollah, killing three members and seriously wounding three others" in a residential building in al-Rihab on the edges of Dahieh. The region has not been evacuated and several people were injured.

The U.N. force in Lebanon said Monday that one of their peacekeepers was killed when a projectile hit one of their positions, where Israeli forces are fighting Hezbollah.

Indonesia confirmed on Monday that one of its peacekeepers was killed in Lebanon.

Lebanon's health ministry said on Sunday that Israeli strikes had killed 1,238 people in the country since the start of the latest war with Hezbollah on March 2.

Iran's ambassador will not leave Lebanon despite being declared persona non grata and ordered to leave the country by Sunday, an Iranian diplomatic source told AFP.

"The ambassador will not leave Lebanon, in accordance with the wishes of the speaker of parliament Nabih Berri and of Hezbollah," the source said, speaking on condition of anonymity.