NEW YORK (AP) — Activist investor Bill Ackman said Monday that he will move to replace most of Allergan’s board of directors as part of a continuing battle for control of the company.

Ackman’s Pershing Square Capital Management and Canadian drugmaker Valeant Pharmaceuticals want to buy Allergan, but the company has rejected their offers. Ackman now wants to call a special shareholder meeting where a vote would be held to replace most of Allergan’s board members. The meeting could happen between early August and late November if enough shareholders back Ackerman’s call

Botox-maker Allergan urged shareholders to hold off taking action on Ackman’s proposal while the company’s board weighs the latest buyout offer.

Valeant Pharmaceuticals International Inc. and Pershing Square made an unsolicited offer to buy Allergan for $45.6 billion in April and have raised it twice. Their latest offer, issued Friday, amounts to $53 billion in cash and Valeant stock. It includes $72 per share in cash for each Allergan share, and Pershing Square says it will not receive any cash if the deal goes through.

Allergan is based in Irvine, California, and its products also include the dry-eye treatment Restasis.

Shares of Allergan Inc. rose $4.61, or 2.8 percent, to $172.07 in afternoon trading. Valeant’s U.S.-traded stock rose $2.45, or 1.8 percent, to $133.66.