A truce aimed at ending more than a year of war in Yemen appears to be largely holding, despite reports of fighting in several places.
The UN-brokered "cessation of hostilities" came into effect at midnight (21:00 GMT on Sunday).
But soon afterwards, the government accused Houthi rebels of violations in the south-western city of Taiz and in Marib, east of the capital Sanaa.
The truce is supposed to set the scene for peace talks in Kuwait next week.
More than 6,300 people have been killed since the conflict in Yemen escalated in March 2015, when a Saudi-led coalition began a military campaign to defeat the rebels and restore the internationally-recognised government.
The UN says most of those killed have been civilians, blaming coalition air strikes for the vast majority of deaths.
The war has also created a humanitarian catastrophe for Yemen, displacing some two million people and leaving 80% of the population in need of aid.
The coalition and Houthi movement both said they would respect the cessation of hostilities, but reserved the right to respond to any attacks.
Within hours of the start of the truce, residents of Taiz, which has been besieged by the rebels, blamed the Houthis for shellfire that killed one civilian and wounded four others.
The rebels meanwhile said there had been at least one coalition air strike in Taiz province, and accused loyalists of being behind violations north and east of Sanaa, as well as in the south.
Despite the reports, the chief-of-staff of the government's forces, Gen Mohammed Ali al-Makdashi, insisted the cessation of hostilities was largely holding.
"The truce has not collapsed and we hope the rebels end their attacks and respect the ceasefire," he was quoted as saying by the AFP news agency.
And a spokesman for the coalition described the violations as "minor".
The UN special envoy to Yemen, Ismail Ould Cheikh Ahmed, said the cessation of hostilities was "critical, urgent and much-needed". "Yemen cannot afford the loss of more lives," he added.
Mr Ahmed noted that the truce agreement included commitments to unhindered access for humanitarian supplies and personnel to all parts of the country.
Preparations are also well under way for the start of the Kuwait talks on 18 April.
The talks will focus on five main areas: the withdrawal of militias and armed groups, the handover of heavy weapons to the state, interim security arrangements, the restoration of state institutions, and the resumption of inclusive political dialogue.
Previous rounds of UN-sponsored peace talks have failed to make progress and a ceasefire last December was abandoned after repeated violations.
The Houthis, backed by security forces loyal to longtime former President Ali Abdullah Saleh, took over Sanaa and much of the west of the country in 2014.
The coalition launched its military campaign in March 2015, after President Hadi and members of his cabinet were forced to flee the southern port city of Aden.
Since then, coalition and pro-government forces have managed to retake large parts of the south and set up a temporary capital in Aden, but failed to dislodge the rebels from Sanaa.
Why is there fighting in Yemen?
- Northern Shia Muslim rebels known as Houthis, backed by forces loyal to Yemen's ex-president, took over parts of Yemen, including the capital, Sanaa, and forced the government into exile in March 2015
- The rebels accused the government of corruption and of planning to marginalise their heartland within a proposed federal system
- Forces loyal to the government and Southern militias, aided by Saudi-led coalition air strikes and troops, have since regained control of five southern provinces