 Complete the following phrase:  There were around 70 T-26s in the Republican Army in the beginning of 1937. In February 1937, company-sized detachments of the Tank Brigade participated in the Battle of Jarama. On 14 February 1937 the Tank Brigade, together with the 24th Infantry Brigade, took part in a counterattack and overcame a major Nationalist force, causing about 1000 Nationalist casualties. On 27 February 1937, the Tank Brigade launched five attacks on Nationalist positions without infantry support, but took heavy losses from anti-tank guns 35 to 40 percent of its tanks in some attacks. Nevertheless, the T-26 was used with great success during the 