Residents said six blasts near the 7 July eastern suburb broke the calm, but it was not clear who was responsible, Reuters reported.
The United Nations-brokered the truce deal as part of confidence-building measures at peace talks last week in Sweden to avert a full-scale assault on the port that is vital for urgent aid supplies for millions facing starvation.
A UN-chaired committee formed to oversee the truce and troop withdrawal from Hudaydah city and three ports held its first meeting on Wednesday using video link and phone with representatives from both sides.
Retired Dutch General Patrick Cammaert, chair of the Redeployment Coordination Committee, will travel to Jordan on Thursday, then on to Sana’a and Hudaydah, with a small initial advance team, UN spokesman Stephane Dujarric said.
The ceasefire deal, which covers only Hudaydah, will see international monitors deployed in the city and port with all armed forces pulling out within 21 days of the truce.
The two sides had also agreed a prisoner swap. A Red Cross official said in Geneva on Wednesday they had exchanged lists of a total of 16,000 people believed to be detained.
Hudaydah, the main port used to feed Yemen’s 30 million people, has been the focus of fighting this year, raising fears abroad that a full-scale assault could cut off supplies to nearly 16 million people suffering from severe hunger.
The truce, the first significant breakthrough in peace efforts in five years, is meant to pave the way for a wider ceasefire in the impoverished country and a second round of talks in January on a framework for political negotiations.