Egypt has deployed ground troops and military equipment to support the Yemeni forces to fight the Houthi militants and restore power from them, military sources said on Thursday.
The Egyptian government has denied that troops are involved in the Yemen operation but local sources confirm their arrival.
The troops arrived in Marib province late on Wednesday, the sources said, without giving more details.
The arrival of the troops coincided with intensified Saudi-led airstrikes against the militants in the capital Sanaa and other cities.
Meantime, Sudan is expected to send thousands of its troops to Yemen after other Arab countries that have been participating in the military intervention against the Houthi militants.
Saudi Arabia, Qatar, Bahrain, the United Arab Emirates, Kuwait, Egypt, Sudan, Morocco and Jordan launched the military intervention in late March with the aim to restore power from the Houthis.
In recent days, thousands of Saudi, UAE, Bahraini and Qatari as well as hundreds of tanks, armored cars, Apache helicopters and other equipment have been deployed to Marib.
The reinforcements have already joined the battle to retake this province.
After the battle, they will advance to drive the militants out of the capital Sanaa.
Dozens of civilians were injured and properties affected in overnight air raids in Sanaa, Houthi media reported.
Separately, news agencies reported the United Nations Security Council will meet today to discuss the situation in Yemen.
UN envoy Ismail Ould Cheikh will submit his report to the meeting which is expected to put the spotlight on progress in talks held in Oman and the military developments in the country.
The UN has lately sponsored Yemen talks in Muscat that were attended by the Houthis in a new effort to reach a political solution and then to end the several-months armed conflict.