A U.N. team overseeing the truce in the Yemeni port of Hodeida came under fire Thursday.
No one was injured when bullets struck an armored vehicle carrying chief monitor Patrick Cammaert.
The Yemeni government and Houthi rebels blamed each other for the shooting.
A shared responsibility
U.N. spokesman Stephane Dujarric said both sides needed to make sure everyone with the U.N. was safe.
"It is important to add that all the parties in Yemen are also responsible for the safety of all U.N. personnel. ... We are dealing with a highly volatile environment in Hodeida."
Thursday's shooting came a day after the Security Council approved sending as many as 75 U.N. monitors to Yemen to strengthen last month's cease-fire agreement for Hodeida. The deal also calls on both sides to withdraw their forces in the city.
The deal has generally held, despite occasional skirmishes, but both the rebels and Yemeni government have been slow to fully implement it.
Iran denies charges
Hodeida has been under rebel control. Nearly all food and humanitarian shipments come through the port. Yemen says the Houthis also get Iranian weapons through the port — a charge Iran has denied.
The fighting in Yemen between government forces and the Iranian-backed Houthis has killed thousands of civilians.
Saudi-led coalition airstrikes targeting the rebels have been indiscriminate, wiping out entire neighborhoods and hospitals.
The fighting has made a dire humanitarian catastrophe in Yemen even worse.
U.N. officials say about 80 percent of Yemeni civilians lack enough food, medicine and clean water.
