"We confirm the readiness of our armed forces to respond to any conspiracies by the enemy," the official news agency SUNA quoted the army's Deputy Chief of Staff, General Essameddine Mubarak as saying.

He was addressing the Sudanese Armed Forces (SAF) in Omdurman, the twin city of the capital Khartoum, both of which have been rocked by protests since December 19.

"The armed forces are committed to protect the country and its residents. The forces are aware of the enemy's threat," Mubarak said, without specifying the nature of the threats or who the enemies were.

Angry crowds have been taking to the streets since December to protest a government decision to triple the price of bread. But the demonstrations have grown into anti-government rallies calling on President Omar al-Bashir to step down.

The veteran leader, who swept to power in an Islamist-backed coup in 1989, has rejected calls to step down, and blamed the violence on "infiltrators" among the demonstrators.

Officials say 30 people have died in protest-related violence since the demonstrations began, while rights groups say more than 40 people have been killed.

Saudi Arabia meanwhile announced its backing for Khartoum.

"The cabinet emphasised the Kingdom of Saudi Arabia's solidarity with the Republic of Sudan as it faces economic challenges," read the minutes of a cabinet session published by the state-run SPA news agency.

A Saudi government delegation visited Sudan last week to boost trade ties, SPA said.

Saudi Arabia and Sudan are key allies in a coalition fighting Iran-backed rebels in Yemen in a war that has triggered what the UN calls the world's worst humanitarian crisis.

Saudi Arabia's Gulf rival Qatar has also backed the Sudanese government, which has also received sustained support from its neighbour Egypt.