(Updates with quotes from White House spokesman)
WASHINGTON Feb 27 (Reuters) - The White House warned Russia on Thursday to respect Ukraine's sovereignty and territorial integrity and told Moscow to avoid "provocative" actions with regard to the crisis-hit country.
"We strongly support Ukraine's territorial integrity and sovereignty. We expect other nations to do the same," White House spokesman Jay Carney told a briefing.
Russian President Vladimir Putin ordered 150,000 troops to be ready for war games near Ukraine on Wednesday, and on Thursday, Russia put fighter jets on combat alert.
"We are closely watching Russia's military exercises along the Ukrainian border, which they announced yesterday. We expect Russia to be transparent about these activities and to avoid provocative actions," Carney said.
"We urge them not to take any steps that could be misinterpreted or lead to a miscalculation during a very delicate time."
The White House's warning echoed those of other top U.S. officials, including U.S. Secretary of Defense Chuck Hagel and Secretary of State John Kerry.
Kerry told Russia on Wednesday it would it would be a "grave mistake" to intervene militarily in Ukraine and said it was considering $1 billion in U.S. loan guarantees and additional funding to help Kiev.
"The U.S., together with Europe and others, stands ready to supplement an IMF program to cushion the impact of reforms on low-income Ukrainians," Carney said on Thursday.
"When it comes to U.S. assistance, we are continuing to consider a range of options ... including loan guarantees to support ... Ukraine economically." (Reporting by Jeff Mason; Editing by Doina Chiacu)