announcer: from nbc news in washington, this is meet the press with david gregory. good morning. israel is stepping up its attacks on gaza despite international pressure for a cease fire. for the first time, evidence of a potential ground invasion as israel briefly send commandos into gaza and warned some residents to evacuate their homes. palestinian authorities saying more than 170 people have been killed. in israel air raid sirens as far north as tel aviv are sounding as hamas continues to launch rockets into the country causing damage and injuries but no deaths. i m joined by martin indyk in his first television interview since stepping down last month as the obama administration mideast envoy. he served as u.s. america s ambassador to israel during the clinton administration. nice to see you. thanks for being here. thanks for having me. so what is next? what s the calculation? is it a ground invasion to stop the hamas rocket fire? i think prime minister netanyahu is