"It is terrible what is happening there. It is simply a civil war, the most terrible civil war," Foreign Minister Sergei Lavrov was quoted as saying by the Interfax news agency at a news conference in Odessa, Ukraine.

"If you think about the fate of the Yemen people, the Yemen state, then of course all those involved in these events should sign agreements, based on the initiative of the Gulf Cooperation Council (GGC)," Lavrov was quoted as saying.

Embattled Yemeni President Ali Abdullah Saleh last month refused to sign a plan brokered by the GGC for him to step down in return for immunity and the country to be ruled by an opposition-led national unity government.

Russia had earlier insisted that Yemen's government and its opponents should resolve the conflict without international mediation, with Lavrov saying in April that "the opposing sides have to seek a solution within their state."

Russia is evacuating some of its embassy workers from Yemen and is considering moving out all Russian nationals, a diplomatic source was cited as saying in Moscow on Saturday by the RIA Novosti news agency.

"Due to the complex situation in Yemen, a process of optimisation is going on at the Russian embassy in Sanaa. Currently we can say that we will send 14 people to Moscow on the next plane," the diplomat said.

"We are considering the option of evacuating all Russians. According to our information, there are around 1,000 people," the diplomat said, adding that Russia could also assist in evacuating citizens of some other countries.