An air strike hits a military site controlled by the Houthi group in Yemen's capital Sanaa, May 12, 2015. [Photo/Agencies]

An aid shipment arrived at the port of Hodeida on Friday, a spokesperson for the Office of the UN High Commissioner for Refugees (UNHCR) said also on Tuesday, adding that preparations were underway for a possible huge airlift of humanitarian aid if the pause in fighting holds.

The plan is for three flights to bring in 300 tons of sleeping mats, blankets, kitchen sets and plastic sheeting, spokesperson Adrian Edwards said.

The Security Council's statement said members emphasized that for the humanitarian pause to be successful, all parties will need to "transparently and reliably suspend military operations", and called on all sides to comply with international humanitarian law.

The Council also urged all parties to allow for the entry and delivery of essential relief items to the civilian population, including urgently needed food, medicine, and fuel, and to facilitate the field activities of humanitarian agencies, in coordination with the Yemeni government.

The Security Council reaffirmed their strong commitment to the unity, sovereignty, independence, and territorial integrity of Yemen, and its commitment to stand by the Yemeni people, the statement said.

Yemen has been mired in political gridlock since 2011 when mass protests forced former President Ali Abdullash Saleh to step down.

Three-year reconciliation talks failed to resolve the crisis but created a huge power vacuum that has potentially benefited the powerful al-Qaida and other extremist groups in the Arabian Peninsula.

Yemen is the base of al-Qaida in the peninsula, a powerful offshoot of the jihadist militant group, which has carried out suicide attacks on Houthi supporters.

The terrorist group Islamic State (IS), also known as ISIL or ISIS, is also gaining ground in the country.