Tehran: A senior Iranian military official has warned the Saudi-led coalition targeting Yemeni militiamen that blocking an Iranian aid ship bound for Yemen will “spark a fire,” as a five-day humanitarian ceasefire appeared to hold early Wednesday after going into effect the day before.

“I bluntly declare that the self-restraint of Islamic Republic of Iran is not limitless,” General Masoud Jazayeri, the deputy chief of staff, told Iran’s Arabic-language Al Alam state TV late on Tuesday.

“Both Saudi Arabia... as well as the Americans and others, should be mindful that if they cause trouble for the Islamic republic with regard to sending humanitarian aid to regional countries, it will spark a fire, the putting out of which would definitely be out of their hands.”

Iran says the ship, which departed on Monday, is carrying food, medicine, tents and blankets, as well as reporters, rescue workers and peace activists. It says the ship is expected to arrive at Yemen’s port city of Hodeida next week. Iran’s navy said on Tuesday it will protect the ship.

Saudi Brigadier General Ahmad Asiri, a military spokesman, said on Tuesday that no ship would be permitted to reach Yemen unless there was prior coordination with the coalition, and that if Iran wants to deliver humanitarian aid it should do so through the United Nations.

In Washington, US Army Colonel Steve Warren said the American military is monitoring the cargo ship and warned that it would not be helpful if Iran is “planning some sort of stunt.” He said the Iranian naval escort is not necessary and that Iran should send the cargo vessel to Djibouti, where humanitarian efforts for Yemen are being coordinated.

The US, which supports the coalition, and Saudi Arabia have accused Iran of arming the Yemeni militiamen, known as Al Houthis. Iran supports them, but both Tehran and the Al Houthis deny it has provided weapons to them.

A five-day humanitarian ceasefire began on Tuesday night, just hours after Saudi-led warplanes targeted Al Houthi militiamen and their allies.

There were reports of continued ground fighting in some areas, with security officials and witnesses saying fierce combat broke out about a half-hour after the ceasefire began when militiamen, tried to storm the southern city of Dhale, firing tank shells, rockets and mortars. But no air strikes by the Saudi-led coalition were reported.

The conflict has killed more than 1,400 people — many of them civilians — since March 19, according to the UN. The country of some 25 million people has endured shortages of food, water, medicine and electricity as a result of a Saudi-led naval, air and land blockade.