Liberty's offer of $25.75 per share for the Mobile, Alabama-based company, is at a premium of about 47 percent to its Friday close.
Liberty Shipping Chief Executive Philip Shapiro was critical of International Shipholding's non-response to the deal.
"Your dilatory tactics, including your continuing refusal to meet with us, only raise questions regarding the ISH Board's commitment to maximizing value for all its shareholders," he said in a letter to the board of International Shipping.
Shares of International Shipping were trading up $1.14, or 6.5 percent at $18.60 in noon trade on the New York Stock Exchange. This is the only dry bulk stock, which has risen so far on Monday's trade.
Shapiro also said despite the global financial crises that is negatively affecting the terms of any financing, his company is still committed to the deal.
"Despite recent events, we have increased our position in the company since we made our offer public. As of today we control more than 9 percent of ISH's outstanding shares," Shapiro said.