Yemeni President Ali Abdullah Saleh is urging his supporters to rally in Sana'a, where opposition activists have been staging two months of mass protests demanding his ouster.
Yemen's state-run Saba news agency says the "solidarity" demonstration Saleh has called for Friday already has drawn many people to the capital - including tribal chiefs, clerics, civil society figures, youths and farmers.
Thousands of Saleh's opponents rallied in Sana'a and other Yemeni cities Thursday to call for an immediate end to his 32-year rule.
Several Yemeni army officers joined the protesters in Sana'a, the latest examples of a wave of defections by Yemeni troops, politicians and diplomats who have turned against Saleh in recent weeks.
The anti-government activists also blame Saleh for the fatal shootings of opposition protesters by his supporters.
President Saleh has offered to hand over power after new elections are held, possibly before the end of his current term in 2013.
Yemen's opposition coalition has rejected such proposals as political maneuvering.
It issued a statement Wednesday calling for the formation of a five-member presidential council to lead the country for a six-month transitional period. The opposition also demanded the dissolving of Yemeni sate security forces and the closure of the information ministry.
An American-born al-Qaida-linked Yemeni cleric has issued a statement welcoming the recent turmoil in Yemen and other Arab nations.
In a message posted on an Islamist website, Anwar al-Awlaki said the uprisings provide an opportunity for Islamists to spread their influence in the region.
Some information for this report was provided by AP, AFP and Reuters.