Starwood Hotels & Resorts said Monday it was weighing an improved takeover bid from a group led by Chinese insurer Anbang rivaling its agreed deal with Marriott International.

In the latest turn in the bidding war for the US hotel operator, Starwood said the consortium led by Anbang Insurance proposed Saturday to pay $82.75 per share, an all-cash deal valued at $14 billion.

That tops Marriott's bid which the Starwood board is still recommending, Starwood said in a statement. Marriott's cash-and-stock offer was worth $13.6 billion when Starwood said on March 21 that it had accepted the sweetened bid.

Starwood said that it had received an improved offer from Anbang on Saturday of $81 per share but that following discussions, the consortium sweetened it again, to $82.75.

"There can be no assurance that discussions will result in a binding proposal from the consortium, that the Starwood Board will determine that any such proposal is a 'Superior Proposal' or that a transaction with the consortium will be approved or consummated on any particular terms or at all," said Starwood in a statement.

Anbang, with assets of $254 billion, is on a shopping spree in the US hotel sector after scooping up the landmark Waldorf Astoria Hotel in Manhattan for nearly $2 billion in 2014.

Starwood said its stockholder meeting to consider the merger with Marriott would convene Monday as previously announced and be immediately adjourned until April 8.

Starwood shares jumped 2.5 percent to $84.21 in morning trade, and Marriott surged 4.2 percent to $71.49.

Their agreed merger would combine Marriott's more than 4,400 properties worldwide, with a portfolio of brands including The Ritz-Carlton, JW Marriott and Gaylord Hotels, with Starwood's 1,270 properties in 100 countries and the Sheraton, Westin and W brands among others.

It would help Marriott expand in China, India and Europe, regions where Starwood has a strong presence.